A replacement sounds...horrible, given what I know--not much--about the shoulder joint.
I've had one surgery on each shoulder (impingement repairs that my doc described as "the six-inch putt of shoulder surgeries"). My ortho has a very good success rate in his surgeries, and is considered
the shoulder specialist in the area. I'd be happy to pass along his contact info, if you like--but he's in the Phoenix area and that may not be of much help.
I can sympathize with you. When my shoulders were giving me problems, anything I did just HURT. I couldn't sleep comfortably, I couldn't sit comfortably, and I couldn't stand comfortably.
I was having to get cortisone injections more and more frequently, and my doc finally said it was time to bite the bullet. I'm glad I did--I'm back at 100% now.
I wish you the best of luck with this.