My shoulder keeps dislocating years after original dislocation. How do I make my shoulders stronger?

I am currently 20 years old female and my shoulder originally dislocated when I was 15 years old. My right shoulder came out originally when I fell off a skate board and it positioned its self back within a few seconds. Two other incidents occurred when I was play fighting with a friend and he pulled my right arm out and again it slid back in the socket. A year later I got into a real fight and when I punched my right arm on impact got forced out the socket and this time it did not position back into place. I had to visit the hospital. Since then my shoulder dis locates on many occasions. When I tried resting the right arm, the left one got over worked and dislocated also. I have to always sleep on my side or back because if I extend my arms up while I sleep my shoulders dislocate. Also I cannot play certain sports because my arm can be swung out the socket. I never took physical therapy because I do not have insurance. I want to work out now but my shoulders are too weak to lift weights continously. I need help to know if there is certain light weight exercises I can do to improve shoulder strength. Also is there certain types of foods that Improve muscle or ligament strength. Please help me I need any advice. This has been a problem for 5 years and happens all the time & I am getting tired of waking up with a dislocated shoulder and I have to pop it back in myself. It is very uncomfortable and makes my shoulder ache after the Incident. PLEASE HELP!!