Kidney stones generally cause pain in the back, just below the ribs, according to Mayo Clinic. Over time, it spreads to the lower abdomen and groin. The pain often fluctuates and grows worse with urination.
Kidney stones begin as small crystals in the urine. Often these small stones pass in the urine without notice; however, The Merck Manual Home Edition indicates that if they do not pass and the urine becomes concentrated, the crystals join together to form larger stones in the ureter or bladder, which are more likely to cause pain.
A change in diet helps to prevent the formation of some kidney stones. Diets high in animal source proteins and vitamin C increase the chances of stone formation. Dehydration concentrates salts responsible for forming stones. The Merck Manual Home Edition recommends patients with a history of stone formation drink eight to 10 10-ounce glasses of water daily to prevent them from recurring.
If stones block the flow of urine from both kidneys, they can cause kidney damage, according to WebMD. For an otherwise healthy person, damage does not occur unless the stone blocks urine flow for two weeks or longer. Such stones may require surgery to restore the urine flow.