Health2wealthclub . I had no clue what was responsible other than I may have been "overusing" my lower back because of how often I trained. What a line of bullshit that was. The reason I had lower back pain had nothing to do with my back, rather with tight hamstrings and quads, horrible hip mobility, and tight piriformis. In other words, my ass and hamstrings would spasm, and pull on all the other muscles in my posterior chain, thereby leaving me a cripple for a weekend. Back Pain = Body Pain When we're talking about lower back pain – or any pain for that matter – we tend to forget that our body works as a whole, and certain antagonists can either be direct or indirect. One major cause of lower back pain is sacroiliac misalignment, and since the piriformis originates on the sacrum, when it's tight, this can cause a variety of problems. Also, your sciatic nerve runs through, or close to (depending on your personal anatomy) your piriformis, and dysfunction of the piriformis muscle can cause signs and symptoms of pain in the sciatic nerve distribution; that is, in the gluteal area, posterior thigh, posterior leg, and lateral aspect of the foot. Another major cause of lower back pain can be from excessive pelvic tilt, whether anterior or posterior.