Lifestyle

5 Signs of Kidney Stones Most People Mistake for Back Pain

By Erica Coleman · August 19, 2026

Your lower back hurts. You blamed the mattress, the yard work, or sitting too long. Then the pain moved — and nothing you did made it stop.

More than half a million Americans visit the emergency room for kidney stones every year, and one of the most common reasons for the delay in seeking treatment is that the early pain feels exactly like a pulled muscle or ordinary back strain. The kidneys sit just below the rib cage against the back muscles. When a stone begins to move, the pain starts in a location most people associate with their spine, not their urinary tract.

The pain is on one side — not across the whole back. Muscle strain typically produces symmetrical soreness or pain that spans the lower back. Kidney stone pain is almost always one-sided, concentrated in the flank area between the lower ribs and the hip. If the pain is sharp, deep, and confined to one side of your back, the source may not be muscular.

The pain moves downward toward your groin. This is the clearest diagnostic signal. Back muscle pain stays where it started. Kidney stone pain migrates — starting in the flank, traveling down through the lower abdomen, and sometimes reaching the groin or inner thigh as the stone moves through the ureter. Pain that travels downward on one side is the body tracing the path of the stone.

It comes in waves rather than staying constant. Muscle pain is usually steady and worsens with movement. Kidney stone pain arrives in intense waves — severe cramping that peaks, eases slightly, then peaks again as the ureter contracts to push the stone through. These waves, called renal colic, are described by patients as among the most intense pain they’ve ever experienced.

You feel nauseous or you’re vomiting. Back pain from a muscle strain doesn’t cause nausea. Kidney stone pain frequently does — the severity of the pain triggers a vagal nerve response that produces nausea, vomiting, and sweating. If your “back pain” is accompanied by an upset stomach and you haven’t eaten anything unusual, the combination points to your kidneys.

Your urine looks different. Pink, red, or brown urine — or urine that appears cloudy or smells unusually strong — is one of the most definitive signs that the pain is kidney-related. Blood in the urine occurs when the stone scrapes the lining of the ureter as it moves. A pulled muscle doesn’t change the color of your urine. A kidney stone does.

The risk factors include dehydration, high-sodium diets, family history, obesity, and certain medications. Diagnosis typically requires a CT scan, which can identify a stone’s size and location in minutes. Small stones may pass on their own with pain management and hydration. Larger stones may require lithotripsy (sound waves to break the stone) or surgical removal. If your back pain is one-sided, comes in waves, and doesn’t improve with rest — especially if your urine has changed — it’s worth calling your doctor before assuming it’s a muscle problem.