compartment syndrome help

I am an experienced female runner that started having tightness, heaviness, fullness and pain in the back of my calves nine months ago.  After multiple MRI's , x-rays, nerve and vascular tests (all negative), several orthopedists believe I have exertional posterior compartment syndrome.  I tried physical therapy, resting for weeks at a time, massage, stretching, muscle strengthening and cross training with no success.  Can you help me find specialists in southern California with experience in testing and treating  posterior compartment syndrome? I would greatly appreciate help!