Piriformis syndrome is usually a neuromuscular problem once the piriformis muscle mass (a pear-formed muscle while in the buttocks) compresses the sciatic nerve (a nerve that extends from your lower spine the many way all the way down to the foot). This leads to pain in the buttocks and hips. https://www.theorthopaedicandpainpractice.com/lower-back-and-buttock-pain/