When your lower back and hip hurt on the same side, it is usually one problem felt in two places, not two separate injuries. Lower back and hip pain together comes from one of three sources: the sacroiliac joint where the spine meets the pelvis, the small facet joints of the lower spine, or an irritated nerve root. Each refers pain into the buttock and hip in a recognisable pattern.

Why do lower back and hip pain travel together?

Your lower back, pelvis and hip are not separate machines. They share nerve supply, so signals from a spinal joint and from the tissue over your hip arrive at the same part of the spinal cord. Your brain then guesses where the trouble is, and it often guesses wide.

They also work as one unit. Every step passes force from the leg, through the hip, across the pelvis and into the spine, so irritation at one point changes the load on the rest. The useful question is not which one hurts, but which structure is producing both.

The sacroiliac joint: the most common shared source

The sacroiliac joint, often shortened to SI joint, is where the base of your spine meets the back of your pelvis. There is one on each side. It barely moves, but it transfers your whole body weight into your legs.

Sacroiliac joint pain sits just below the belt line, off to one side. People can usually point to it with one finger, just inside the bony bump at the back of the pelvis, and it spreads from there into the buttock and the back of the hip.

It is worse standing on one leg, rolling over in bed, climbing stairs, and in the first steps after getting up from a chair. It is more common in pregnancy and the months after birth, and it can start after a fall onto the buttock.

The lumbar facet joints: worse when you lean back

Each level of your lower spine has a pair of small joints at the back, called facet joints. They guide movement and stop the spine sliding too far, and like any joint they can become irritated.

Facet pain is worse when you lean backwards and worse when you stand still for a long time. It is often eased by sitting, or by leaning forward onto a shopping trolley.

It refers into the buttock and the back of the hip, but rarely below the knee. Pain that stops above the knee, with no pins and needles, fits the facet joints better than a nerve.

When a nerve root is involved

Pain that travels below the knee, especially with tingling or numbness, points to an irritated nerve root rather than a joint. This is lumbar radiculopathy, and it needs a different assessment. Our guide to what sciatica feels like covers that pattern.

What about arthritis in the hip joint itself?

Wear in the hip joint is a real cause of pain, but the pattern differs. It hurts in the groin more than the back, and it is worse on weight bearing. Plenty of people have both a worn hip and an irritated lower back, and back and hip pain together is exactly what they feel.

Lower back pain on the left side above the hip

Lower back pain on the left side above the hip is a common search, and the honest answer is that the side rarely changes the diagnosis. The same structures sit on both sides, and the same problems affect them. Left is no more worrying than right.

That spot most often points to the sacroiliac joint, the lumbar facet joints at that level, or irritation of the quadratus lumborum, a deep muscle between the lowest rib and the top of the pelvis.

Left sided pain with abdominal symptoms, urinary symptoms or a fever needs a different assessment, because the kidney and bowel sit close by.

What makes it worse, and what that usually points to

• Worse leaning backwards, or standing still for a long time: the lumbar facet joints.
• Worse standing on one leg, or climbing stairs: the sacroiliac joint.
• Worse rolling over in bed, or getting up from a chair: the sacroiliac joint.
• Worse sitting for long periods, eased by standing: a lumbar disc.
• Travels below the knee, with tingling or numbness: a nerve root.
• Felt in the groin, worse on weight bearing: the hip joint itself.

None of these is a diagnosis, only a starting point.

Back and hip pain in pregnancy and after birth

Pain across the lower back, pelvis and hips is common in pregnancy and the months afterwards. It often involves the sacroiliac joints and the joint at the front of the pelvis, and it has a name: pelvic girdle pain.

It is a recognised condition, not something to endure quietly, and it hurts most when the legs move independently: walking, stairs and turning in bed.

What actually helps

Start with movement and load. Complete rest tends to make these joints more irritable, not less. Breaking up long periods of standing and easing off the activities that reliably flare it does more than resting everything. Physiotherapy aimed at the hip and trunk muscles then gives the pelvis better support, reducing the strain landing on the joints.

When pain has lasted months, an interventional pain clinic adds the ability to test which structure is responsible. A sacroiliac joint injection is placed under live imaging, so the medication reaches the joint itself rather than nearby tissue.

For the facet joints, we use diagnostic medial branch blocks. A small amount of freezing is placed on the tiny nerves carrying signals from one facet joint. If your pain settles temporarily, that joint is likely the source. If nothing changes, we look elsewhere. When blocks confirm it, radiofrequency ablation can interrupt those same nerves for longer. Responses vary from person to person, which is why blocks come first.

Warning signs that need urgent care

Most back and hip pain is not dangerous. These are the exceptions. Seek same day care if you have:

• Numbness in the groin or saddle area, the part that touches a bicycle seat
• New problems controlling your bladder or bowel
• Weakness in both legs
• Back pain with a fever
• Back pain that started after a significant fall
• Unexplained weight loss alongside your back pain
• New severe back pain and a history of cancer
• Night pain that does not ease whatever position you move into

Frequently asked questions

Can lower back problems cause hip pain?
Yes, and it is one of the most common reasons for hip pain. The sacroiliac joint and the lumbar facet joints both refer pain into the buttock and back of the hip, so it is genuinely felt there even though the source sits in the back or pelvis. Groin pain is more often the hip joint.

Why do my lower back and hips hurt on one side only?
One sided pain usually means one side is loaded or irritated more than the other. The sacroiliac joint is a frequent cause, because it takes weight unevenly whenever you stand on one leg. Facet joint irritation and muscular pain also settle on one side.

Is pain in the lower back and hips different in women?
The structures are the same, but pregnancy, birth and hormonal changes affect the pelvis, so sacroiliac and pelvic girdle pain are seen more often in women. The pattern is otherwise similar and the same assessment applies. Causes outside the spine are also considered when pain does not vary with movement.

How do I know if it is my back or my hip?
Location and triggers help. Groin pain worse on weight bearing points to the hip joint. Pain below the belt line to one side, worse on stairs and rolling in bed, points to the sacroiliac joint. Pain worse on leaning backwards points to the facet joints.

This article is general information, not medical advice. It cannot diagnose your pain. If your symptoms are new, worsening, or worrying you, speak with your family doctor or contact us for an assessment.

Talk to us about back and hip pain

If your lower back and hip have hurt together for months and physiotherapy has not changed it, an assessment can establish which structure is responsible. Silver Pain Centre in Toronto offers image guided sacroiliac joint injections, diagnostic medial branch blocks and radiofrequency ablation, and most services are covered by OHIP with a physician referral.

Ask your family doctor to send a physician referral, or use our self referral form to start without one.