I've been through physical therapy for tendonitis. In conjunction with icing the area in question, this only mildly alleviated pain. While gaining full range of motion was the first priority (accomplished in about a month I think) the problem of pain was still there. The pain went down with PT but never went completely away when moving the shoulder with tendon problems out or up over the head.

The best thing you can do is find someone to find the bike fit that meets all your requirements. They need to take your specific ailments and large frame into consideration so you can get a bike that is comfortable and doesn't cause you more pain.

Cheers, Al