Forget the chiropractor. Get yourself to a good D.O. or physical therapist. Make sure they know how to evaluate you for Sacroiliac Joint Dysfunction. You may have to see several people to find someone who really understands this. Go to www.kalindra.com for self-education on this. The sciatic nerve can be irritated when the piriformis muscle goes into spasm and tightens around it. Piriformis spasm is one of the many secondary aspects of SI joint dysfunction. Good luck.