Stone pain is usually caused by renal colic, which is a severe pain in the lower back or lower abdomen caused by ureteral stones. Most renal colic is actually ureteral colic, which is caused by spasm of the smooth muscle of the renal pelvis or ureter. The pain is more intense, with paroxysmal attacks, along with nausea, vomiting, and in severe cases, blood in the urine. The patient’s pain is usually colicky and is often accompanied by radiating pain in the lower abdomen or inner thighs in the male scrotum or labia majora in women. Ureteral peristalsis and movement of the stone can aggravate renal colic, and the pain is most noticeable where the obstruction occurs. The pain of kidney stones is usually localized distension and does not cause severe pain.