At a crossroads- arthroscopy of shoulder or physical therapy

Hi, I'm a fifteen year old softball player fairly well acquainted with medicine and the procedures done for shoulder pain. I have had shoulder pain for about 2 years, due to improper throwing mechanics. I think a possible cause of this pain is due to altered throwing mechanics from elbow physical therapy 6 months before the onset of my shoulder symptoms.
My shoulder pain began around two years ago, gradually increasing in intensity and frequency. Initially, the pain was upon throwing, and lasted about five minutes after stopping the throwing motion. It has progressed to the point where I have pain/ stiffness/ clicking at rest and doing normal everyday activities, and I have not thrown for a month and a half.
About 4 months after the pain started, I was put on a vigorous (and painful) physical therapy regimen, which I did not do as much as advised because it seemed to make the pain worse.
My high school ball season started in October with twice-weekly weightlifting sessions. The bar weighs 45 pounds, and I weigh 100. Needless to say, I tried to do the squats "through the pain" to avoid being looked down upon by the coach (it was my freshman year). I quickly got a doctor's note after about two weeks of workouts, but the damage was (further) done.
The season officially started in late January, with 2 1/2 hour practices every day, and the pain got much worse, to the point where sleeping was difficult and writing (the pain is my dominant arm) was a chore. I went to see an orthopedic surgeon who suggested that I get cortisone injection, along with an MRI. This was in the middle of the season, so I rested it for a week afterwards and the shot had little effect (worked for about 3 weeks).
The MRI was done and revealed no major defects (full thickness rotator cuff tears, large SLAP lesions, etc.) of my shoulder. The surgeon recommended rest, but I played through the end of the season (early June).
I had little improvement in the five weeks that followed, restricted to no throwing. I went to see the orthopedic surgeon about three weeks ago and he said that we are basically at a crossroads. He gave me my second cortisone injection at that appointment and instructed me to begin physical therapy in two weeks, which I did. I have various periscapular strengthening exercises, using the red theraband and one lb weights. I have been doing them every day since I saw the therapist (four days). The decision that I have run into is- do I a) continue with the physical therapy and see if improvement happens or b) have an exploratory shoulder scope with a removal of the bursa sac (subacromial decompression)? The doctor said to go ahead and schedule the surgery, and we could cancel if we felt the therapy is helping enough, so it is currently scheduled for July 28th.
There are a few complicating factors to the decision:
1. I have Driver's Ed scheduled for three weeks from now (two weeks form the surgery date). Will the surgery affect this at all? The doctor was very optimistic that I could be driving by this point.
2. I am registered to play field hockey this fall. The doctor said that this was okay because field hockey is played below the waist, but I still have some doubts.
3. School starts August 25th, and I am taking writing-intensive courses. Would a month be enough time for me to write? The doctor said that the recovery was about two weeks, but some of the literature I've read online says otherwise.
4. Finally, my most important concern is is it realistic to expect my shoulder to be 100% if I do the surgery with all the necessary physical therapy and post-operative care afterwards?
Bottom line: I want to play, and play PAIN-FREE.
Also: We asked my pediatrician what she would recommend, and she said that surgery would probably be best because throwing at the intensity that I do would just require cortisone shot after cortisone shot. The surgeon, however, said he tries not to operate unless he feels that it is necessary.
Any help/ advice to making a decision would be GREATLY appreciated.
Thank you.

So did you go through with it? What did they find?

At a young age of 15, I would advise you against any kind of surgery. I suggest you to stick to your physical therapy program and try to give adequate rest to your shoulder.