What Causes Back Pain? Lower Back Pain Causes Explained

Back pain affects most adults at some point, and lower back pain is one of the leading causes of time off work in the UK. The reassuring news is that most back pain is mechanical, coming from the muscles, ligaments and joints of the spine, and is not caused by serious damage or disease. Often no single structure can be blamed, and the pain settles within a few weeks.

This guide explains what causes back pain, the less common specific causes, why scans rarely help and the warning signs that need a doctor straight away.

Quick answer

Most back pain is non-specific mechanical pain, triggered by things such as lifting, twisting, a sudden movement, long hours sitting, inactivity, poor sleep or stress. Specific causes include a slipped disc pressing on a nerve, arthritis in the spinal joints and narrowing of the spinal canal. Rarely, back pain is caused by an infection, a fracture or cancer. Numbness around the genitals or buttocks, or new bladder or bowel problems, needs a 999 call.

Non-specific back pain

Around nine in ten cases of lower back pain are described as non-specific. This means the pain is real but comes from the normal structures of the back, such as muscles, ligaments and small joints, rather than from a specific injury that a scan would show. It often starts after an awkward movement, though sometimes there is no obvious trigger at all.

Common triggers

• Lifting, bending or twisting, especially when tired or unaccustomed to the task
• Long periods of sitting, driving or standing in one position
• Inactivity and deconditioning, which leave the back and hip muscles less able to cope with load
• A sudden increase in activity, such as gardening, decorating or a new gym routine
• Poor sleep and stress, which increase muscle tension and pain sensitivity
• Excess weight and smoking
• Pregnancy, when changes in posture and ligaments put extra strain on the back and pelvis. See pelvic girdle pain in pregnancy.

Specific causes of back pain

• Slipped disc. Part of a disc bulges and can press on a nerve, causing pain down the leg known as sciatica. See what a slipped disc feels like.
• Facet joint pain. Irritation of the small joints at the back of the spine, often worse leaning backwards or twisting.
• Spinal stenosis. Narrowing of the spinal canal, usually in older adults, causing leg pain or heaviness when walking that eases when sitting or bending forward.
• Spondylolisthesis. One vertebra slipping forward on another, sometimes seen in young athletes and older adults.
• Inflammatory back pain. Conditions such as axial spondyloarthritis usually start before 45, cause morning stiffness lasting more than 30 minutes, improve with exercise and may wake you in the second half of the night. These need a GP referral.
• Osteoporotic fracture. A small fracture in a weakened vertebra, sometimes after a minor fall or even a cough.

Why does my lower back ache?

A dull ache that is worse in the morning or after sitting, and eases as you move, is very typical of mechanical back pain and stiffness. Pain that builds up through the day may reflect posture, load or fatigue. Changing position often, staying active and strengthening the back and hips usually helps. If you sit for long hours, see the silent damage of sitting all day.

What causes upper back pain?

Upper back pain, between or around the shoulder blades, is most often caused by muscle strain and posture: long hours at a desk or on a phone, carrying heavy bags or sleeping awkwardly. Stiffness in the joints of the middle back and tension in the neck and shoulders can also refer pain there, and occasionally it comes from an irritated nerve in the neck. The NHS advises seeing a GP if back pain is coming from the top of your back rather than the lower back, and upper back pain with chest pain needs a 999 call. See upper back pain between the shoulder blades and neck and shoulder pain.

Causes of lower back pain in women and men

The common causes are the same for everyone: strains, long periods of sitting, deconditioning and disc or joint problems. A few causes are more specific.

• Women. Period pain and endometriosis can cause a low, dragging ache in the lower back that follows the menstrual cycle. Pregnancy puts extra load on the back and pelvis, and the fall in oestrogen after the menopause increases the risk of osteoporosis and spinal fractures. See endometriosis.
• Men. Heavy lifting and physical work are frequent triggers. Inflammatory back pain such as ankylosing spondylitis has historically been diagnosed more often in men, and prostatitis can cause an ache in the lower back, pelvis and groin, usually with problems passing urine.

Do I need a scan?

Usually not. Scans often show age-related changes, such as disc bulges or wear in the joints, in many people with no pain at all, so they rarely explain the pain or change treatment. UK guidance advises against routine X-rays and MRI for low back pain. Imaging is useful when there are warning signs, when nerve symptoms are getting worse, or when surgery is being considered.

Where the pain sits can point to the cause. Our guides cover middle back pain, lower right back pain, lower left back pain and back spasms in more detail.

What helps

Staying active, gentle exercise, heat and strengthening the back and hips help most back pain, and exercise has the strongest evidence for recovery and preventing recurrence. For practical steps, see how to relieve back pain naturally, and if pain travels down your leg, how to relieve sciatica pain.

Back pain: when to worry

Severe back pain is not always serious. A muscle spasm or strain can be intensely painful for a few days and still settle well with gentle movement and simple pain relief. What matters more than how bad the pain feels are the signs that come with it. The lists below explain which symptoms need urgent help and which mean you should see your GP.

Call 999 or go to A&E if:

• Back pain comes with numbness around the genitals, buttocks or inner thighs, new difficulty controlling your bladder or bowels, or weakness in both legs. These can be signs of cauda equina syndrome
• Upper back pain comes with chest pain, breathlessness or sweating
• You develop sudden, severe pain in the back or abdomen, especially if you are older or smoke

See your GP promptly if:

• You have a fever or feel generally unwell with back pain
• You have unexplained weight loss or a history of cancer
• The pain started after a significant fall or injury, or you have osteoporosis
• Pain is constant, severe, getting worse and does not change with position, including at night
• You have pain in your side with a fever or problems passing urine, which may be a kidney problem
• You have new back pain and are under 20 or over 50
• Pain is worse when you cough, sneeze or go to the toilet, or you notice a lump or swelling in your back
• Pain has not improved after a few weeks of looking after it at home, or it is stopping you doing everyday activities

If you feel hot, shivery or generally unwell with back pain, or severe pain starts suddenly or is getting worse quickly, ask for an urgent GP appointment or call 111.

Frequently asked questions

Can stress cause back pain?

Stress does not damage the spine, but it increases muscle tension and pain sensitivity and can make back pain last longer.

Can a mattress cause back pain?

An old or very soft mattress can contribute to morning stiffness. Many people find a medium-firm mattress more comfortable than a very hard one.

Is back pain a sign of kidney problems?

Occasionally. Kidney pain is usually felt higher up, in the side, and often comes with fever, pain passing urine or feeling unwell. Most lower back pain is not kidney-related.

Why does my back hurt when I wake up?

Morning stiffness is common with mechanical back pain and usually eases within half an hour of moving. Stiffness lasting longer than 30 minutes, especially if you are under 45, is worth discussing with your GP.

Why does my lower back hurt when lying down or at night?

Mechanical back pain often stiffens up when you lie still for a long time, especially on a soft mattress, and eases once you get moving. A pillow between the knees when lying on your side, or under the knees when lying on your back, can make lying down more comfortable. Pain that is constant at night, does not ease with changing position, or comes with fever or weight loss is different and should be checked by a GP.

Why does my lower back hurt when I walk?

Walking can aggravate a strained back or irritated facet joints. In older adults, back and leg pain or heaviness that builds up with walking and eases when you sit or lean forward is typical of spinal stenosis. Pain spreading below the knee with pins and needles suggests an irritated nerve, as in sciatica. A physiotherapist can work out which applies and what will help.

Back pain assessment in Chiswick

If your back pain is not settling, an assessment identifies what is driving it and sets an exercise programme at the right level. At Omnia Lifestyle, physiotherapy in Chiswick starts with a 70-minute initial assessment and treatment for £99 with an HCPC-registered physiotherapist. For muscle tension and spasm, deep tissue massage and sports massage start from £65 for 30 minutes, and physiotherapist-led MSK therapy combines hands-on treatment with exercise. Traditional acupuncture is £80 for 60 minutes; see acupuncture for back pain. Home visits are available when travelling is too painful.

Omnia Lifestyle is at 8 to 9 Bedford Corner, The Avenue, Chiswick W4 1LZ, close to Turnham Green station, on bus routes 94, E3 and 272. Limited parking is available on request when booking.

Read more about back pain and sciatica, explore physiotherapy, manual therapy and acupuncture, or book an assessment.

This article is general information, not medical advice. If you have any of the warning signs listed above, seek medical attention.