Kidney stones, or renal calculi, are solid masses made of crystals. Kidney stones usually originate in your kidneys, but can develop anywhere along your urinary tract.The urinary tract includes the kidneys, ureters, bladder, and urethra.Kidney stones are known to be one of the most painful medical conditions.ecognizing the Symptoms and Signs of a Kidney Stone. Kidney stones are known to cause severe pain. Symptoms of kidney stones may not occur until the stone begins to move down the ureters. This severe pain is called renal colic. You may have pain on one side of your back or abdomen.