The most telling sign of a kidney stone is intense, wave-like pain between your lower ribs and hip on one side of your body. This pain often radiates to your back, groin, or lower abdomen, and it can shift location as the stone moves through your urinary tract. If you’re also noticing changes in your urine or a burning sensation when you pee, a kidney stone is a strong possibility.
What the Pain Feels Like
Kidney stone pain is distinctive. It’s a sharp, serious pain in your side and back, just below the ribs. Most people describe it as coming in waves: intense for several minutes, easing off, then returning. This happens because the tube connecting your kidney to your bladder (the ureter) spasms as it tries to push the stone through.
The location of your pain can actually tell you where the stone is in its journey. When the stone is still high up near the kidney, the pain tends to concentrate in your flank and back. As it moves lower, the pain shifts toward your lower abdomen and groin. Some people feel it in the front of the abdomen, which is why kidney stones are sometimes confused with other conditions. Unlike a pulled muscle or a steady ache, kidney stone pain changes. It can be excruciating one hour and nearly gone the next, then return with full force.
Urinary Symptoms to Watch For
Pain isn’t the only clue. A kidney stone irritates the lining of your urinary tract as it moves, producing several noticeable changes in how you urinate:
- Discolored urine. Pink, red, or cola-colored urine signals blood in the urine. Even a tiny amount of blood can change the color noticeably.
- Burning during urination. A stone near the bladder or in the lower ureter can cause a sharp, burning sensation when you pee.
- Frequent urges. You may feel like you need to urinate constantly, sometimes with urgency, but only pass small amounts each time.
- Cloudy or foul-smelling urine. This can indicate either the stone itself or an accompanying infection.
Not everyone gets all of these symptoms. Some people notice blood in their urine before the pain even starts. Others have intense pain but urine that looks completely normal to the naked eye. Microscopic blood, invisible without a lab test, is present in most cases.
Nausea, Vomiting, and Other Body Reactions
A kidney stone doesn’t just affect your urinary system. When a stone blocks urine flow, the kidney swells and the ureter spasms. This triggers a cascade of reactions throughout your body. Nausea and vomiting are extremely common during intense pain episodes, not because anything is wrong with your stomach, but because the nerve signals from your kidney and gut overlap. Some people also experience sweating, restlessness, and an inability to find a comfortable position. You might pace, shift from standing to lying down, or curl up, none of which fully relieves the discomfort.
How Kidney Stone Pain Differs From Other Conditions
Several conditions can mimic kidney stone pain, and knowing the differences helps you figure out what you’re dealing with.
Appendicitis pain typically starts around the belly button and migrates to the lower right abdomen, settling there and steadily worsening. Kidney stone pain, by contrast, comes and goes in waves, can occur on either side, and shifts as the stone moves. Appendicitis also tends to cause loss of appetite and abdominal swelling, which kidney stones generally don’t.
A urinary tract infection (UTI) shares some overlap with kidney stones: both cause burning during urination and frequent urges. The key difference is that UTIs don’t usually produce the severe flank pain that kidney stones cause. That said, stones and infections can occur together. Certain types of kidney stones actually form because of chronic UTIs, so having symptoms of both at once is possible and worth getting checked out quickly.
How Kidney Stones Are Diagnosed
If you suspect a kidney stone, a doctor will typically order two things: a urine test and imaging.
A urine test (urinalysis) checks for red blood cells, crystals, and signs of infection. It’s fast and can point strongly toward a stone, though it can’t confirm the size or location. Blood tests may also be drawn to check for elevated calcium or uric acid, both of which contribute to stone formation, and to make sure your kidneys are functioning properly.
The gold standard for confirming a kidney stone is a non-contrast CT scan. It picks up stones with 95 to 100 percent sensitivity, meaning it catches nearly every stone regardless of size or composition. It also reveals how large the stone is, exactly where it’s lodged, and whether it’s causing a backup of urine in the kidney. Ultrasound is sometimes used, particularly for pregnant women or children, but it detects stones only about 45 percent of the time, so a negative ultrasound doesn’t rule one out.
Will It Pass on Its Own?
Most small kidney stones pass without any procedure. The likelihood depends heavily on size. Stones 4 millimeters or smaller pass on their own about 72 percent of the time. At 5 millimeters, the rate drops to around 60 percent. Interestingly, 6-millimeter stones pass at about 72 percent as well, likely due to their location in the urinary tract at the time of diagnosis. Once stones reach 10 millimeters or larger, only about 27 percent pass spontaneously, and most of those will need medical intervention.
Passing a stone can take anywhere from a few days to several weeks. During this time, your doctor will likely recommend drinking plenty of water to keep urine flowing and may prescribe medication to relax the ureter and ease the stone’s passage. Pain management is a central part of the process, since the waves of pain can be severe enough to bring people to the emergency room.
How to Collect Your Stone
If your doctor confirms a stone and expects it to pass, you’ll be asked to strain your urine at home. This matters because analyzing the stone tells your doctor exactly what it’s made of, which directly determines how to prevent the next one. And prevention matters: once you’ve had one kidney stone, you’re significantly more likely to develop another.
You’ll use a kidney stone strainer, a small device with fine mesh that you urinate through every single time until the stone passes. The stone may look like a grain of sand or a tiny piece of gravel, so check the strainer carefully after each use. When you find it, place it in a clean, dry container with a lid. Don’t wrap it in tissue, tape it down, or add any liquid. Return it to your doctor or lab as instructed. Stones can pass at any time of day or night, so consistency with straining is important.
Red Flags That Need Immediate Attention
Most kidney stones, while painful, resolve without serious complications. But certain symptoms signal that the stone is causing a dangerous problem. Fever combined with flank pain suggests an infection behind the blockage, which can become life-threatening quickly. Inability to urinate at all means the stone may be completely blocking urine flow, which puts pressure on the kidney and can cause lasting damage. Vomiting so severe that you can’t keep fluids down is another reason to head to the emergency room, since dehydration worsens the situation and makes it harder for the stone to pass.