Kidney stone pain is not usually constant. It typically comes in waves that last 20 to 60 minutes, with periods of relief in between. That said, some people do experience a steady, dull ache that persists alongside or between those sharper episodes. The pattern depends on where the stone is, whether it’s moving, and how much it’s blocking urine flow at any given moment.
Why the Pain Comes in Waves
The wave-like pattern has a specific biological explanation. When a kidney stone gets stuck in the ureter (the narrow tube connecting your kidney to your bladder), it blocks urine from draining. That backup of urine increases pressure inside the kidney, which triggers a chain reaction: the body releases chemicals that cause the ureter’s muscles to contract harder and faster than normal, trying to push the stone along. Those intense muscle contractions are what you feel as a sharp, cramping wave of pain.
When the muscles contract too hard for too long, lactic acid builds up, the same way it does in any overworked muscle. That buildup triggers inflammation, which makes the next wave of pain even worse. The cycle repeats each time the stone shifts position and re-obstructs urine flow. Between episodes, when the stone moves just enough to let some urine pass, the pressure drops and the pain eases temporarily.
The Dull Ache Between Waves
Many people notice a low-level, constant soreness in their back or side even during the “quiet” periods between sharp waves. This background ache comes from the kidney itself swelling with backed-up urine, a condition called hydronephrosis. As long as the stone partially blocks the ureter, some degree of swelling and pressure persists, producing that nagging discomfort that never fully goes away until the stone passes or is removed.
If the obstruction becomes complete, meaning no urine can get past the stone at all, the dull ache can intensify into a more persistent, unrelenting pain rather than the typical wave pattern. This is one reason some people describe their kidney stone pain as constant while others describe it as coming and going. Both descriptions can be accurate depending on the degree of blockage.
Where You Feel It Changes Too
The location of the pain often shifts as the stone moves through the urinary tract. It typically starts as a deep ache in the lower back or side, between the ribs and the hip. As the stone travels down the ureter toward the bladder, the pain can migrate to the lower abdomen and groin. Men sometimes feel it in the testicles. This migration can happen over hours or days, and it’s actually a good sign. It means the stone is progressing toward the bladder, where it will eventually pass out of the body during urination.
Stone Size Doesn’t Predict Pain Severity
One of the more surprising findings in kidney stone research is that bigger stones don’t necessarily cause worse pain. A study published in the American Journal of Emergency Medicine found no correlation between stone size and pain scores. A tiny 2-millimeter stone can produce excruciating pain if it lodges in a narrow part of the ureter, while a larger stone sitting in the kidney without causing obstruction might produce little discomfort at all. What matters most is location and the degree of blockage, not size.
Other Symptoms That Come With the Pain
Kidney stone pain rarely shows up alone. When a stone blocks the ureter and the kidney swells, the intense nerve signals can trigger nausea and vomiting. This happens because the kidneys and the digestive tract share nerve pathways, so severe kidney pain can essentially confuse the gut into reacting as well. You may also notice blood in your urine (which can look pink, red, or brown), a frequent urge to urinate, or a burning sensation when you go.
Signs the Pain Needs Urgent Attention
Most kidney stones pass on their own, but a stone that completely blocks the ureter can cause urine to back up and create a breeding ground for bacteria. If a kidney infection develops on top of the obstruction, it can become serious quickly. The warning signs that distinguish a routine (if miserable) stone episode from something more dangerous include a fever or chills, feeling shivery or unusually weak, and urine that looks cloudy or smells foul. These symptoms together suggest infection behind the blockage, which typically requires prompt treatment rather than waiting for the stone to pass naturally.