Piriformis syndrome is a neuromuscular issue when the piriformis muscle mass (a pear-formed muscle while in the buttocks) compresses the sciatic nerve (a nerve that extends from your lower backbone each of the way all the way down to the foot). This results in pain in the buttocks and hips. https://www.theorthopaedicandpainpractice.com/lower-back-and-buttock-pain/