Aching pain deep in the buttock and down the posterior thigh may indicate Piriformis Syndrome. Symptoms are often worse when sitting or driving.
Low back issues often cause the piriformis muscle to tighten up as a protective mechanism. Because this muscle lies close to the sciatic nerve, its spasm can mimic sciatic symptoms. Tightening of the piriformis muscle often corresponds to poor abdominal, gluteal and core strength.
Myofascial release of the piriformis muscle coupled with a stretching exercise can help relieve tightness and pain. Ultimately, treatment must focus on the underlying causes, normally hip muscle imbalance and/or lumbar spine issues (see related sections).