Piriformis syndrome is a pain in the butt but treatable. Have you felt pain in the hip? Pain in the center of your butt? Or even pain down the back of the leg? You may be suffering from a condition called piriformis syndrome. The piriformis is a muscle that runs from the middle of your sacrum (or tailbone) to the outer hip bone (trochanter). This muscle may be working overtime on your body. From athletes to the workaholic this muscle gets overused.