Causes of Back Pain
Back pain is a symptom rather than a single diagnosis. Several structures can produce pain, including muscles, ligaments, spinal joints, intervertebral discs, nerves and, less commonly, organs outside the spine. In many uncomplicated cases, no single structure can be identified as the definite source. Clinicians call this nonspecific back pain, and it is very common. (1, 2)
Muscle Strain and Ligament Sprain
A sudden twist, unfamiliar workout, prolonged awkward posture, or heavy lift can overload the muscles and connective tissues supporting the spine. Pain may feel aching, tight, or sharp with certain movements. Muscles sometimes become guarded or spasm, making it difficult to straighten up. Such episodes can be intensely painful without indicating serious structural damage. Gradual movement, modified activity, and time often help. Complete bed rest is generally discouraged. (2, 3)
Age-Related Disc and Joint Changes
Spinal discs act as cushions between vertebrae. With age, discs may lose water content and height, while facet joints may develop osteoarthritis. These changes are often described as degeneration or spondylosis. Importantly, MRI and X-ray frequently show disc bulges and degenerative findings in people who have no pain at all. An imaging finding is not automatically the cause of symptoms; it must be interpreted alongside the examination and the pattern of pain. (5, 6)
Herniated Disc and Sciatica
A herniated disc occurs when disc material extends beyond its usual boundary. If it irritates or compresses a nerve root, pain may radiate from the lower back into the buttock, thigh, calf, or foot. This is commonly called sciatica or lumbar radicular pain. Tingling, numbness, or weakness may accompany it. Not every disc herniation causes symptoms, and many symptomatic herniations improve with nonsurgical care. Persistent or progressive neurological problems require reassessment. (2, 4, 7)
Spinal Stenosis
Spinal stenosis means narrowing of spaces through which nerves travel. Lumbar stenosis may cause aching, heaviness, tingling, or weakness in one or both legs, especially while standing or walking. Symptoms often ease when sitting or leaning forward, such as over a shopping trolley. This characteristic pattern is called neurogenic claudication. Stenosis becomes more common with age, but imaging severity does not always match symptom severity. (4, 8)
Fractures, Inflammatory Conditions, and Other Causes
Vertebral compression fractures may follow a fall or occur with minimal trauma in people with osteoporosis. Inflammatory back pain, sometimes associated with axial spondyloarthritis, can feature prolonged morning stiffness, pain at night, and improvement with movement rather than rest. Less common but important causes include infection, cancer involving the spine, and referred pain from the kidneys, abdomen, or pelvis. These possibilities become more relevant when the history contains specific warning signs. (1, 4, 9)
Factors That Increase the Risk of Back Pain
Previous back pain episodes, low physical activity, smoking, obesity, repetitive physical loads, and some workplace demands are associated with back pain. Sleep difficulties, persistent stress, anxiety, and fear of movement can influence how intensely pain is experienced and how long disability lasts. This does not mean pain is imaginary: pain involves physical tissues, the nervous system, and a person's broader health circumstances. Treatment is often most successful when it addresses several contributing factors rather than searching for a single “damaged” structure. (1, 2, 3, 10)

