Spasm that shoots down the back of your leg from your hip? Pain that radiates down your hamstring? Numbness that reminds you something is wrong? Hip pain when sitting? All of these are symptoms of piriformis syndrome which can go from irritatingly tolerable to painfully debilitating. This condition is literally something that you can say a pain in the butt because the piriformis muscle is located in the buttock region that compresses the nearby sciatic nerve and cause pain that starts in the buttocks and radiates down the back of the leg into the hamstring muscles and sometimes even the calf muscles.