A kidney stone can move from the kidney and become lodged inside the ureter, which can block the flow of urine, as well as cause a sharp cramp in the back, side, or lower abdomen. Pain often comes in waves lasting up to two hours, then subsides, called renal colic. The affected kidney could then develop hydronephrosis, should a part of the kidney become swollen due to blocked flow of urine. It is classically described that there are three sites in the ureter where a kidney stone will commonly become stuck: