you could try to use positive reinforcement. when ever she talks to a stranger or does something that she's normally scared of do something special. let her stay up half an hour late at night or get a piece of candy or something. That way she'll learn that things arent as scary as she things they are. I would do this in addition to going to a doctor though because it does sound like social anxiety disorder. I wouldnt force her to play on a team. Like someone else said, it could just make it worse