For what it's worth, 5 years ago I really hurt my left shoulder (and more) at age 50. I took a dump on my motorcycle due to gravel, and went down hard on that side. I didn't go to the doctor either, even though I probably should have. I couldn't lift it higher than shoulder level, and I'm pretty sure I tore the muscles/tendons pretty bad.
Anyway, the shoulder eventually healed fine all by itself, BUT, it took 1.5 years to do so. The only real things I did to help it, was to keep it moving as much as possible, so I wouldn't end up with "frozen shoulder". Later on, I did some light exercise with 2 lb weights. Men tend to use far more weight than they need to when exercising. 2 lb's is plenty for rehab, IF you use proper lifting techniques.
It takes a LOT longer for soft tissue injuries to heal, than say broken bones. You can pretty much guarantee something like this will take over a year to heal, even if you are much younger than I am.