If the stone blocks the pelvic outlet during activity or during the flow of blood and urine, the urine in the kidney cannot be discharged, resulting in different degrees of hydronephrosis, which can produce obvious pain. When the position changes or the stone leaves the original obstruction site, so that the renal pelvis ureter regains its patency, the hydronephrosis gradually reduces, so the pain also gradually reduces or disappears. It is also possible for a kidney stone to drain into the ureter, which can cause spasm of the ureter and cause significant pain. However, as the ureter peristalsis, the stone reaches a non-obstructed site again, and then the spasm is reduced and the pain can also be reduced. Therefore, as long as kidney stones exist in the body, they can cause pain at any time, and need to be treated with extracorporeal shock wave lithotripsy, medication or surgery.