I will second Dave Cutter's sentiments. Personally, I would try a physical therapist or a sports medicine doc before giving up hope. I have used chiropractors for shoulder and lower back issues but I don't know that I would like them manipulating my spine above the shoulders. I would also strongly consider the possibility of a recumbent bike/trike if you really want to pursue cycling. I'm 69 and ride a road bike alongside 30, 40 and 50 year old's. I don't know how much longer I'm going to be able to do that as I am slowly starting to feel the effects of it. My wife rides a recumbent trike that I rode yesterday for 25 miles. It's a blast to ride and if I can no longer ride my road bike, for whatever reason, I don't think I will need too much convincing to go the recumbent trike route. I live in Florida, so we don't have any hills, per say, to worry about where a recumbent bike/trike will be an issue.

Best of luck in finding a solution to your shoulder problem so you can continue with your riding.