okiediver (and others) - How soon did your issues arise after your THR? My 3-month anniversary from my right THR is tomorrow. I've had an easy recovery and have been pain free for weeks until about two weeks ago. Groin pain started about then and has been increasing, sounding very similar to what you all describe. I guess I would have expected this to crop up sooner after the surgery, as I have been walking 2 miles at a time and biking since the 6-week mark.
I haven't been back to my surgeon yet - just starting to research what might be causing the pain and this thread definitely caught my eye! I'm trying to see if there are stretches, exercises, etc., that might help. Really pretty bummed by this setback.
P.S. - I'm also an okie (Tulsa) and diver.