Quadratus lumborum muscle and back pain.

One of the most common causes or low back pain is trigger points in the quadratus lumborum muscle or Q.L. for short. This muscle is located in the lower back and is responsible for trunk and pelvic movement and stabilization. This muscle often harbors trigger points that form from prolonged sitting or bending. Pain from trigger points in this muscle will cause pain in the low back, sacrum, and into the hip.

Piriformis syndrome

Piriformis syndrome is a condition in which the piriformis muscle, located in the buttock region, spasms and causes buttock pain. The piriformis muscle can also irritate the nearby sciatic nerve and cause pain, numbness and tingling along the back of the leg and into the foot (similar to sciatic pain).