Read the other threads dude, instead of assuming what will happen and getting ahead of yourself. You don't know if an operation's necessary yet.
You'd have to get a couple of opinions from docs rather than post here. Other than having an operation, my advice on the other threads stands-i had more than one cortisone shot and managed to avoid problems without any operation from then on by avoiding the problem-causing exercises after recovering either naturally or with the help of cortisone-once recovered you have to stay away from the problem causers.
If/when recovery occurs, don't continue to "work through" exercises that cause problems.
I agree with Pumpster. Not knowing your particular situation, it might be something functional you can correct like posture. Allowing your scapulae to roll forward can increase the likelihood of impingement syndromes. In this case, attention could be paid to scap. stabilizers (rhomboids/lower traps) to help retract your shoulders.
However at 48, you could have a bone spur which is causing the impingement, in which case, they'd see this on CT/MRI and surgery "might" help.
Calcification in the tendons also mimics impingement pain syndromes, soft tissue work from your chiropractor might clear it up.
Finally, people, be wary of how many cortisone shots you're getting in a year. While it might be safe once or twice in the year, if you are continually getting them and relief is not permanent, it's probably not fixing anything. Continued cortisone injections puts you at risk of losing bone density and thus stress fractures.