Well, without a clinical evaluation it would be difficult to determine the cause of your symptoms. Possibilities that may need to be considered include fractures, dislocations, injuries to the ligaments, tendons, inflammations like bursitis, tendonitis, neuro-muscular/ vascular causes, spinal causes etc. I would suggest getting this evaluated by an orthopedician for an accurate diagnosis and appropriate management.
Hope this helps.
This could be a SI problem. See a P.T that specializes in the pelvic girdle.