C.W.
Is it your hip flexor muscle? I messed mine up in the Marines when my ankle rolled the wrong way on a rough terrain hike. It never heals if that's what it is... I was told that by the officer at medical. It flares up randomly, a lot of times when I run a lot or when I'm going on long drives... last year it hurt SO bad in the theater that it was almost unbearable. You can try to do butterfly kicks where you lay on your back and lift one leg straight up and down and do the same with the other leg.. for me it actually causes it to flare up but it is hit and miss.
If it is your hip flexor muscle, which I believe they do call what your title says, then it won't heal and you'll need to watch out for your knee because if that is what your describing I have a tear in my knee because I favored the leg or something....(still trying to get the Marines to pay for it *rolls my eyes*)
Update:
It may be that though, I can't create the pain. Very true about that. When I messed up my hip I could barely get into my mustang without being in serious pain right where everything comes together at my hip. Just hope that that isn't what it is because it never fully heals... it sucks when it just randomly flares. A lot of times when I do hip flexor exercises and most of the time nothing happens, like I said mind of its own lol. Just cross your fingers it's not that lol. Sometimes they can do MRI when it is hurting to try and pinpoint where it is happening... do they plan on doing that with you? I believe they advised me with my hip condition to rest it... with what I have you can't strengthen it or whatever, you just try not to overdue it. So maybe you can try that if strengthening it doesn't work.