I had surgery years ago to repair my shoulder. It popped out in an accident and was never the same again. I decided to have it repaired.
Having a shoulder out of commission is an adjustment. I learned to do a lot of things with my arm in a sling. The pain really was no big deal. I think I only wore the sling for a month or too. I agree that doctors are usually conservative, and that you may well progress faster than they tell you to expect. Definitely follow the instructions you are given.
My strongest memory of my shoulder experience was leaving my key in the room and having to enter my second story room one handed. The hard part was launching myself from the window to my bed. I landed on it in a heap and immediately went to sleep. Quite exciting, living with one arm.
Paul