The piriformis may spasm because of muscular weakness. Muscles LOVE to compensate for other muscles that aren't carrying out their position. This comes about lots While using the piriformis. Sciatica — The sciatic nerves run from the lower back, in the buttocks and down the back of your legs. Sciatica https://www.theorthopaedicandpainpractice.com/lower-back-and-buttock-pain/