Hey Alpine. I'm getting ready for a long ride so I have to keep this short.
First, try to book a massage. Second try to do these stretches:
http://www.easyvigour.net.nz/fitness/h_TFL_StrSt.htm
http://www.easyvigour.net.nz/fitness...xorstretch.htm
I recommend stretching for 20 sec, 4 reps per session and 2 sessions per day.
If those don't work, see a physical therapist with manual therapy training. You might have a pelvic alignment issue and that could be why it's not improving with rest.