I also was just casted a few days ago to immobilize for 4-6 weeks. I've been suffering for almost 3 years and have tried everything. My Doc seems pretty optimistic about this approach.
At least it's less painful walking around with the cast than without it now that the inflamation has settled down. I'm learning to walk better so my alternate side hip doesn't hurt, but certainly there's the possibility of pain in other areas to compensate.
Good luck, Lets stay hopeful!