The earliest sign of a kidney stone is usually a dull ache in your side or lower back that intensifies into sharp, wave-like pain as the stone moves from the kidney into the ureter, the narrow tube connecting your kidney to your bladder. About half of all kidney stones that sit quietly in the kidney without symptoms will eventually cause problems within five years. Knowing what those first signals feel like can help you act quickly when they appear.
How the Pain Starts and Builds
A stone sitting inside the kidney itself often causes no pain at all. Symptoms typically begin once the stone shifts and enters the ureter, where it can block urine flow, cause the kidney to swell, and trigger spasms in the ureter wall. That’s when you feel it.
The pain usually begins as a dull, persistent ache on one side of your back, just below the ribs. Over the next hour or two, it often sharpens into intense, stabbing waves that can radiate down into your lower abdomen and groin. Men sometimes feel it in the testicles. These waves of pain, called renal colic, tend to last anywhere from 20 to 60 minutes before temporarily easing, then returning. The pain is typically at its worst one to two hours after it first starts.
One hallmark of kidney stone pain is that you can’t find a comfortable position. Unlike muscle pain that improves when you lie still, stone pain makes you restless. You may pace, shift constantly, or curl up without relief. This restlessness is a useful clue that something more than a pulled muscle is going on.
Changes in Your Urine
Before the major pain hits, or alongside it, you may notice your urine looks different. Blood in the urine is one of the most common early indicators. It can appear pink, red, or cola-colored, though sometimes the amount of blood is so small it’s only detectable under a microscope during a lab test. If your urine changes color without an obvious explanation like beets or certain medications, a stone is a likely possibility.
You might also notice you’re urinating more frequently or feeling an urgent need to go, especially if the stone has traveled to the lower part of the ureter near the bladder. The urine may look cloudy or have a stronger smell than usual. These urinary changes can appear before the intense pain does, making them worth paying attention to as potential early warnings.
Nausea, Vomiting, and Other Body Responses
Kidney stone pain is intense enough to trigger a whole-body response. Nausea and vomiting are extremely common during an acute episode because the kidneys and the gut share nerve pathways. When the kidney and ureter are under stress, signals spill over to the digestive system, producing waves of nausea that mirror the waves of pain.
Some people also experience sweating, a racing heart, or a general sense that something is seriously wrong. Fever and chills are not typical of an uncomplicated stone. If you have pain along with a fever, that combination suggests the stone may have caused a urinary infection, which is a more urgent situation requiring prompt medical attention.
Stone Size and What It Means for Symptoms
Not every kidney stone announces itself dramatically. Whether you feel symptoms depends largely on the stone’s size and location. Stones smaller than 4 millimeters (roughly the width of a pea) generally pass on their own within one to two weeks, and about 80 percent of people with stones this small need nothing beyond pain relief. Stones larger than 5 millimeters are much less likely to pass without help, particularly if they’re lodged in the upper or middle ureter, where passage rates for larger stones drop to near zero.
Smaller stones in the lower ureter, closer to the bladder, have the best odds of passing naturally, around 74 percent for stones under 5 millimeters. Location matters as much as size. A small stone high up in the system can cause just as much pain and blockage as a larger one sitting closer to the exit.
How to Tell It Apart From a UTI
Kidney stone symptoms overlap with urinary tract infections enough to cause confusion, since both can involve frequent urination, urgency, and discomfort. A few key differences help separate them.
- Pain location: UTI pain in women typically centers in the lower abdomen near the pubic bone. Kidney stone pain tends to start in the back or side of the lower torso.
- Pain quality: UTIs usually cause a burning sensation during urination. Kidney stone pain is sharper and more stabbing, often coming in waves unrelated to urination.
- Blood in urine: While both can cause it, visible blood is more characteristic of kidney stones.
- Fever: A UTI commonly causes fever. An uncomplicated kidney stone typically does not. If you have stone-like pain plus fever, the stone may have triggered an infection.
It’s also worth noting that kidney stones and UTIs can occur together. A stone that blocks urine flow creates a setup for bacteria to grow, so one condition can lead to the other.
Symptoms That Need Immediate Attention
Most kidney stones, while painful, resolve without lasting harm. But certain combinations of symptoms signal a situation that can’t wait. Pain paired with fever and chills suggests an infected, obstructed kidney, which can become dangerous quickly. Inability to keep fluids down due to persistent vomiting raises the risk of dehydration. Complete inability to urinate means the blockage may be severe. And pain so intense that over-the-counter medication doesn’t touch it warrants emergency evaluation, both for relief and to confirm the diagnosis.
Who Gets Kidney Stones
Kidney stones are remarkably common. Globally, over 105 million new cases were recorded in 2021. They affect men roughly twice as often as women, though the gap has been narrowing. Peak onset is between ages 30 and 60, and if you’ve had one stone, your chances of developing another within the next five to ten years are roughly 50 percent.
Dehydration is the single biggest modifiable risk factor. People who live in hot climates, work outdoors, or simply don’t drink enough water form more concentrated urine, which allows minerals to crystallize. Diets high in sodium, animal protein, and oxalate-rich foods (spinach, nuts, chocolate) also increase risk. A family history of stones roughly doubles your likelihood, suggesting a genetic component to how your body handles calcium and other minerals.
What to Do When You Suspect a Stone
If you’re experiencing a new, unexplained ache in your side along with any urinary changes, the most useful first step is to drink plenty of water. Staying well-hydrated increases urine volume and helps push smaller stones through. Pay attention to the color of your urine and whether you notice any blood.
Over-the-counter anti-inflammatory pain relievers are generally the most effective option for stone pain, as they reduce the swelling in the ureter that contributes to the blockage. If the pain becomes severe, comes in waves, or is accompanied by fever, vomiting, or blood in the urine, getting evaluated promptly with imaging (typically a CT scan) will confirm whether a stone is present, how big it is, and where it’s located. That information determines whether you can safely wait for it to pass or whether you’ll need a procedure to remove it.