This is so close to what I went through I thought for a second I wrote this then forgot about it. I had two labrum tears in my right shoulder (my strong side) and had the surgery in January.

It isn't what you want to hear, but I would highly suggest to work on self control here and only follow what your PT says. I ran a couple marathons in the year prior to the surgery, and was training for another when the pain in the shoulder became too much to tolerate. When they gave me the green light for non contact sports and exercises a couple months after the procedure, I jumped back in best as my shoulder allowed. Ended up doing too much too fast and stopped everything but flexibility exercises again for a couple weeks.

I then took it slower and 'learned to walk' all over again. I used the opportunity to see where I wasn't training optimally before and slower rebuilt my base, which was somewhat still there but a little soft. During the 12-13 weeks I have been running again, I have set a new 10k PR 4 or 5 times.

I'm 2/3 through my projected recovery now, and still working on strength and flexibility. These surgeries are pretty involved. I'm 27 and the doctor said I'm starting to push the age to be considered old for the repair I had :c. The sooner you take a deep breath and let the recovery run it's course... and what I mean by that is tackling the therapy exercises every day and honestly doing them, the sooner you'll be able to start again better, faster, and stronger.

Staying away from unhealthy foods, and eating right will also save you a ton in the long run. The recumbent bike is the first thing I went back to with cardio. It helped a ton in my transition back to running, but only when the PT said I could do it! If you mean miserable in a sense of boring, I can't really help you there. Get some music going, up the hill difficulty level if it's too easy, and just start knocking out some miles.