I haven't had one, I think Vanders has. I do have a good mate (not on this forum) who's had one done and the other can't be fixed. He's doing cortisone shots once or twice a year and spends three days a week in the gym for a couple of hours.
Mostly shoulders can be repaired with some good posture, gym work and attention to the specific muscles..... I'll play devil's advocate here and ask the question. Is your surgeon offering you any other alternative than an operation? If not, he's perhaps in it for the money.... just sayin'..... and some will disagree. If I'd listened to a doctor, I'd have given up surfing and had an op on my back two years ago, and a shoulder op four years ago, but some specialised exercises have prevented that.
IMO, an op should be your last resort.
That being said, my good mate took about three months to recover enough to be able to paddle well. Make sure your board is a wave catcher and you'll be fine.