Dislocated Shoulder for a teenage boy?

Okay so I just had my second dislocated shoulder of my life and that was about 1 week ago. I have to wear a sling for 3 weeks and have to decide on whether or not I should have surgery or not. Here is my scenario. I am 15 years old and my left shoulder has been dislocated twice. I would say I am an active person as I play basketball and baseball as hobbies. I plan to join my baseball team in about 7 months playing as a pitcher and I am right handed. What do you guys think I should do? Should I just go ahead with PT or do the surgery?
Also I took off my sling after a week when I was showering and let my arm straighten out. It felt stiff but that's obvious. I was surprised however that it was difficult to raise my arm. Is this natural? And is it because my shoulder is too weak and I just need to strengthen it or is it because my shoulder is just stiff and I just need to move it around?
Thanks to anybody that can help!

Subluxations traumatize ligaments, tendons and the lot, so it is normal to lose ROM following injuries such as this. You may need surgery but that is based on clinical and radiograhic evidence of damage to structures. If it is there it won't go away. Even if you have surgery I would strongly recommend going through therapy 1st b/c the better you are going in will determine how well and quickly you bounce back.
Therapy 4 weeks 1st