Understanding The Underlying Causes Of Low Back Pain
- Apr 26, 2023
- 12 min read
Updated: May 23
What's Actually Causing Your Low Back Pain: A Guide to the Root Issues
Low back pain is not a diagnosis — it's a symptom. And that distinction matters enormously, because the right treatment depends entirely on what's actually causing the pain. Too often, people manage their back pain generically — rest, ibuprofen, maybe some stretching — without ever understanding the underlying mechanism. That approach works sometimes. But when it doesn't, you need a clearer picture. This guide walks you through the most common underlying causes of low back pain, what makes each one distinctive, and what actually helps. For a broader introduction, see our ultimate guide to low back pain.
How Common Is Low Back Pain — and Why Does It Matter?
Low back pain is the single leading cause of years lived with disability globally. It affects more people than any other musculoskeletal condition, and its economic and personal costs are staggering.
In 2020, low back pain affected 619 million people globally, with a projection of 843 million prevalent cases by 2050, driven by population growth, aging, and lifestyle changes including higher rates of obesity and physical inactivity.
Despite how common it is, low back pain is frequently misunderstood and mistreated. Understanding what's causing your pain is the first step toward treating it correctly. The three most common causes of low back pain are a useful starting point — and this article goes deeper into the full range of underlying mechanisms.
Key Takeaway: Low back pain affects over 619 million people worldwide and is the leading cause of disability globally. Understanding the specific cause is essential for effective treatment.
Muscle Strains and Ligament Sprains: The Most Common Culprit
The majority of acute low back pain — the kind that comes on suddenly after lifting something heavy, making an awkward movement, or simply overdoing it — is caused by a strain or sprain. A muscle strain is a stretching or tearing of muscle fibers. A sprain is the same thing happening to ligaments. Both are painful, often dramatically so, and both typically resolve within a few weeks with appropriate care. Learn more about how to deal with low back strains and sprains.
Think of your lower back muscles like the cables that hold a suspension bridge in tension. If you put too much sudden load on one cable — or stress it at the wrong angle — it can tear. The bridge (your spine) loses stability immediately, and everything tightens up in response. That protective spasm is your body's way of preventing further damage.
Risk factors for muscle strains include:
Lifting with your back instead of your legs
Carrying loads that are too heavy or unevenly distributed
Sudden twisting or rotational movements
Prolonged sitting followed by abrupt movement
Fatigue — tired muscles are far more vulnerable to tearing
Weak core muscles that leave your lumbar spine without adequate support
Key Takeaway: Muscle strains and ligament sprains cause most acute low back pain. They're painful but usually resolve with conservative care — the key is not making them worse through prolonged rest or poor movement habits.
Degenerative Disk Disease: When Your Spinal Cushions Wear Down
Between each vertebra in your spine sits an intervertebral disk — a tough, rubbery cushion that absorbs shock and allows movement. Degenerative disk disease (DDD) is not actually a disease in the clinical sense — it's the gradual breakdown of these disks over time, primarily through aging. The disks lose water content, become thinner and less flexible, and develop small tears in their outer rings. This reduces their ability to absorb the forces your spine encounters during everyday movement.
What's tricky about DDD is that some people have significant disk degeneration visible on MRI and experience very little pain, while others with moderate changes suffer significantly. The experience of pain depends not just on the structural changes but on how your nervous system processes the signals coming from those changes — which is why treatment for DDD goes well beyond just managing the disk itself.
DDD is also a risk factor for other conditions on this list, including herniated disks, bone spurs, and spinal stenosis. Managing it early — through exercise, maintaining a healthy weight, and not smoking — can slow its progression.
Key Takeaway: Degenerative disk disease is a natural aging process in the spine. Its impact varies widely between individuals. Early lifestyle management can slow progression and reduce its contribution to pain.
Herniated Disks: When the Cushion Ruptures
A herniated disk — sometimes called a slipped or ruptured disk — occurs when the soft inner gel of an intervertebral disk pushes through a crack in its tougher outer layer. When this herniated material presses on a nearby nerve, it can cause significant pain, numbness, or weakness radiating into the legs. This radiating pain, when it follows the path of the sciatic nerve, is known as sciatica.
Herniated disks most commonly occur in the lower lumbar spine and are often the result of years of degeneration followed by a triggering event — sometimes something as mundane as bending over to pick up a bag. Learn more about sciatica and its relationship to low back pain and the full picture of what a herniated disk involves.
Disc degeneration is characterized by disc dehydration, which diminishes the disc's ability to distribute pressure, making it more susceptible to damage and leading to annular tears, fissures, and a higher incidence of herniation.
Key Takeaway: A herniated disk is the result of a degenerating disk's inner material pushing through its outer wall. When it presses on a nerve, it causes radiating pain — often down the leg. Most herniated disks resolve without surgery.
Facet Joint Arthritis: When the Joints Between Vertebrae Wear Down
Your vertebrae are connected by small joints called facet joints, which guide and control the movement of your spine. Like any joint in your body — your knees, hips, shoulders — facet joints can develop osteoarthritis as you age. The cartilage that cushions the joint surfaces breaks down, bones can rub together, and inflammation develops.
Facet joint arthritis typically produces a more localized, aching low back pain that is often worse in the morning, worsens with prolonged standing or backward bending, and tends to improve with movement and gentle exercise. It can be hard to distinguish from other causes without imaging, but the pattern of symptoms often gives strong clues.
Risk factors include age, prior spine injuries, obesity, and previous episodes of significant low back pain. Management mirrors general arthritis treatment: exercise to maintain joint nutrition and mobility, weight management, anti-inflammatory medications, and in some cases targeted injections.
Key Takeaway: Facet joint arthritis is a common cause of chronic low back pain in older adults. It produces a distinctive aching pattern, worse in the morning and with extension, and responds well to exercise and activity.
Spinal Stenosis: When the Space Around Your Nerves Narrows
Spinal stenosis occurs when the spinal canal — the tunnel through which your spinal cord and nerve roots travel — narrows and compresses those nerves. This narrowing is usually the cumulative result of several degenerative changes: thickening of ligaments, bone spur formation, disk bulging, and facet joint enlargement. It's more common in people over 50 and often develops gradually over years.
The signature symptom of lumbar spinal stenosis is neurogenic claudication: pain, cramping, or weakness in the legs that comes on with walking or prolonged standing and is relieved by sitting or leaning forward. Imagine you're walking through a grocery store and your legs start to feel heavy and painful after a few minutes — but sitting down on the nearest bench provides relief quickly. That pattern is classic for stenosis.
Stenosis is managed with physical therapy focused on flexion-based exercises, lifestyle modifications, injections for symptom relief, and occasionally surgery when conservative care fails and symptoms are significantly disabling.
Key Takeaway: Spinal stenosis causes cramping leg pain with walking that improves with sitting. It develops gradually from multiple degenerative changes and is most common in people over 50.
Sacroiliac Joint Dysfunction: An Often-Overlooked Source
The sacroiliac (SI) joints connect the base of your spine (the sacrum) to your pelvis. They're large, strong joints that absorb and transfer load between your upper and lower body. When these joints become inflamed, hypermobile, or restricted in their movement — collectively called SI joint dysfunction — they produce pain that can mimic lumbar disk pain, making diagnosis challenging.
SI joint pain typically presents in the low back and buttock area, often on one side, and may radiate into the back of the thigh. It's commonly aggravated by prolonged sitting, transitioning from sitting to standing, climbing stairs, or lying on the affected side. It's particularly common in pregnant women and in people who have had prior lumbar spine surgery.
Think of it like a car with a wobbling wheel. The problem isn't at the top (your lumbar spine) — it's in the joint connecting two major structures. No amount of treating the spine directly will fix it. The SI joint needs its own targeted treatment: specific manual therapy, stabilization exercises, and sometimes an injection to confirm and treat the diagnosis.
Key Takeaway: Sacroiliac joint dysfunction is a common and frequently missed cause of low back and buttock pain. It requires diagnosis and treatment distinct from lumbar spine conditions.
The Role of Posture, Sitting, and Lifestyle
Modern life is hard on the lower back. Prolonged sitting is one of the most significant modifiable risk factors for low back pain, and the proportion of adults spending most of their day seated has increased dramatically over recent decades. Research shows that reported rates of low back pain among office workers range from 25 to 51 percent — and sitting time is a major contributor.
Occupational ergonomic factors have emerged as the most significant risk factor for the global burden of low back pain, with a considerable proportion of workers spending over 8 hours daily in sedentary positions.
Prolonged sitting compresses lumbar disks, shortens hip flexors (which pull the pelvis forward and increase lumbar lordosis), and disengages the core muscles that stabilize the spine. The result is a back that becomes progressively less able to handle normal loads. Read our tips on 5 things in daily life that cause low back pain for practical ways to address lifestyle factors.
Key Takeaway: Prolonged sitting is one of the most significant modifiable causes of low back pain. Breaking up sitting time, improving workstation ergonomics, and strengthening the core are all evidence-backed strategies.
Psychological and Social Drivers of Low Back Pain
This is the part that surprises many people: your emotional state, stress levels, and social environment are genuine contributors to low back pain. This is not a statement that the pain is "all in your head." It's an acknowledgment that the nervous system — which processes all pain signals — is profoundly influenced by psychological factors. Anxiety, depression, job dissatisfaction, and social isolation all independently increase the risk of developing chronic low back pain and make existing pain harder to treat. Read more about why stress causes back pain and the role of anxiety in low back pain.
This is why effective treatment of chronic low back pain increasingly involves cognitive-behavioral therapy, mindfulness, and other psychological interventions alongside physical care. Addressing the psychological drivers isn't optional — it's often what makes the difference between temporary relief and lasting recovery.
Explore the evidence on top psychological interventions for managing chronic low back pain for a deeper look at this dimension of treatment.
Key Takeaway: Stress, anxiety, and depression are legitimate causes and amplifiers of low back pain — not peripheral factors. Addressing psychological drivers is a core part of effective chronic pain management.
Less Common but Serious Causes to Know
In a small minority of cases, low back pain is a symptom of something more serious. These are the "red flag" causes that warrant prompt medical evaluation:
Compression fractures: Common in older adults with osteoporosis. A fracture can occur with minimal trauma and cause severe, localized pain.
Infections: Spinal infections (discitis, vertebral osteomyelitis) cause persistent pain with fever, are rare but serious, and require prompt treatment.
Tumors: Primary or metastatic cancer can involve the spine. Pain that is constant, worsens at night, and doesn't change with position warrants evaluation.
Cauda equina syndrome: Compression of the bundle of nerve roots at the base of the spine, causing bowel/bladder dysfunction, saddle numbness, and severe leg weakness. This is a surgical emergency.
Referred pain from organs: Kidney stones, kidney infections, endometriosis, aortic aneurysm, and other conditions can refer pain to the lower back.
Red flags that warrant immediate medical evaluation include pain that is severe and constant, occurs at rest or at night, is accompanied by fever or unexplained weight loss, or comes with bowel/bladder changes. If any of these apply to you, do not wait. Read our detailed guide on red flags and when to see a doctor for the full checklist.
Key Takeaway: A small but important minority of low back pain cases have serious underlying causes — fractures, infection, tumors, or organ problems. Red flag symptoms warrant prompt medical evaluation, not home management.
How to Prevent Low Back Pain From the Start
Prevention is always more effective than treatment. Here are the most evidence-backed strategies for reducing your risk of developing low back pain — or reducing its severity if you're already experiencing it:
Exercise regularly: Core strengthening is your spine's best protection. Strong abdominals and multifidus muscles stabilize the lumbar spine and reduce load on disks and joints. See our guide on 5 exercises for a stronger lower back.
Maintain a healthy weight: Every pound of excess body weight increases load on the lumbar spine. Modest weight loss produces significant reductions in back pain in overweight individuals.
Don't smoke: Smoking reduces blood supply to spinal disks, accelerating degeneration and impairing healing.
Lift properly: Always bend at your knees and hips, not your waist. Keep loads close to your body and avoid twisting while lifting.
Break up sitting time: Stand and walk for at least 5 minutes every 45–60 minutes. Consider a sit-stand desk if your job keeps you seated for hours.
Address stress proactively: Mindfulness, exercise, social connection, and professional support all reduce the psychological drivers of low back pain.
Read our full guide on 5 simple tips to keep your back healthy for more detail on each of these strategies.
Key Takeaway: The most effective prevention strategies for low back pain are also the most fundamental: regular exercise, healthy weight, not smoking, smart lifting, and managing stress.
Frequently Asked Questions
What is the most common cause of low back pain?
Muscle strains and ligament sprains are the most common cause of acute low back pain. Degenerative disk disease and facet joint arthritis are the most common causes of chronic low back pain in adults. In most cases, there is no single identifiable structural cause — the pain arises from a combination of physical, lifestyle, and psychological factors.
Can low back pain be caused by something other than the spine?
Yes. The sacroiliac joints, hip joints, and various internal organs can all refer pain to the lower back. Kidney stones, kidney infections, endometriosis, pancreatitis, and even aortic aneurysm can present as low back pain. This is one reason that persistent or unusual low back pain should be evaluated by a physician rather than assumed to be purely musculoskeletal.
How do I know if my back pain is serious?
Red flags that warrant prompt medical evaluation include: pain that is severe and constant, especially at rest or at night; pain accompanied by fever, chills, or unexplained weight loss; recent trauma like a fall; loss of bowel or bladder control; significant leg weakness; or a history of cancer, osteoporosis, or steroid use. Most back pain is not serious — but these warning signs should never be ignored.
Does low back pain always show up on an MRI?
No — and this is one of the most important things to understand. Many serious sources of pain are not visible on standard imaging, and many structural abnormalities visible on MRI cause no symptoms at all. MRI is a tool for ruling out serious pathology and guiding treatment decisions, not a definitive measure of pain severity. A normal MRI does not mean your pain isn't real.
What is the relationship between core strength and low back pain?
The muscles of your core — particularly the deep stabilizers like the multifidus and transversus abdominis — are the spine's primary mechanical support system. Weak core muscles force your lumbar spine, disks, and joints to absorb loads they weren't designed to handle alone. Strengthening your core is one of the most consistently evidence-supported interventions for both preventing and treating low back pain.
Can stress really cause back pain?
Yes. Chronic psychological stress keeps your nervous system in a heightened state of arousal, increases muscle tension throughout your back, and amplifies pain signals. Studies show that people under high occupational or emotional stress are significantly more likely to develop chronic low back pain. Addressing stress is a legitimate and evidence-based part of treatment — not a soft add-on.
What lifestyle changes have the biggest impact on low back pain?
The three highest-impact lifestyle changes are: (1) regular exercise, especially core strengthening and aerobic activity; (2) maintaining a healthy weight; and (3) quitting smoking. Beyond those, breaking up prolonged sitting, improving sleep quality, and managing stress are all supported by evidence. These changes don't just reduce pain — they improve your overall health across multiple systems.
The Bottom Line
Low back pain is not one thing — it's a symptom with dozens of potential causes, ranging from simple muscle strain to complex degenerative conditions to psychological factors that reshape how your nervous system processes pain. The good news is that regardless of the cause, the fundamentals of recovery are similar: stay active, strengthen your core, manage stress, and get appropriate professional support when you need it. Understanding what's actually driving your pain puts you in a far better position to address it effectively. Explore the LivaFortis ultimate guide to low back pain for a comprehensive roadmap, and read our articles on preventing low back pain and 5 exercises for a stronger lower back to start building your recovery plan today.
Written by the LivaFortis Editorial Team | Editorial Standards
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