Have you discussed your concerns about a possible stress fracture with your doctor to see if an MRI or bone scan is justified? The fact that the stretching has not provided relief doesn't surprise me at all. I've had piriformis syndrome and stretching was very ineffective. Jim suggested one test you can try. I'm sure you have found (and tried) everything that others have suggested online. The obvious answer is to get your doctor to authorize further testing.
Meanwhile "stop wishing for bad luck and knockin' on wood".