My 15 year old is really sick and wont back go to the doctor?

Were you in the room with her when the doc examined her? Any reason she might have taken a dislike to the doc? If not, does she have problems with other male figures? It's not like the tests for bronchitis are invasive, not like a Pap for instance. But if this behaviour is coming out of nowhere, you have to wonder what else is going on here. Ask her if she would go to a different doc, but if she refuses I don't know what you can do. She's too big to tie up and carry. But what sane person would not want to be treated for bronchitis.