What can i do?

I have been having some trouble with a shoulder injury over the past few
months. I had a really bad fall while i was in america and nearly
dislocated my collar bone. I rested it and then got physio on it but it
still gets bad sometimes when i am playing during a match. What can i do to stop the shoulder from causing trouble when playing.

I think you should report back to your local sports physio. You should ask for more of a diagnosis before anyone here can comment. Perhaps you need further investigation e.g. MRI etc. You mention playing during a match, but playing what? chess? :D

Unfortunately you do not tell what kind of sport is causing you pain. neither what sort of movement. Neither where the pain is located. Neither if there is any radiation. If there are other areas of pain which might be related to the shoulder. What did the physio treatment consists of what sort of exercises were you given. What did the physio tell you the cause of your pain was. Is there a diagnose of luxation of your collarbone and how was this diagnosed. how long ago did you had your fall. Has it improved since.
Unless you give some more information a reply to your question is a shot in the dark.

I think there is insufficient information provided to comment upon the problem you are facing. The only thing advisble is to consult an orthopaedician or Physio.