Abdominal Strain

I have a recurring hip bursitis and some sacroiliac pain but the recent pain I have is lower quadrant (right) abdominal pain. I’ve had it all checked out – laposcropy, ulatrasound, bone scan, CT scan – it is not a gyno problem and not my appendix. I believe it’s some sort of muscle strain (real shortage of sports docs here!).
I really feel it walking long distances (1 hour or so). I hurt yesterday during a weighted crunch and crossovers can sometimes aggravate it. It seems to hurt in conjunction with my SI joint – all my problems are on the one (right) side. What have I strained now ?!?!?! Is it an abdominal muscle or leg muscle ? The hip flexor stretch, esp. reaching up with the arm on the same side, really seems to get where it hurts. Sitting aggravates it.
Any help is appreciated !