I have a 15 year old who has really bad pelvic pain what should i do?

Have her seen: At age 15, she is old enough to see a physician in private. It is her right to be seen, and promptly. I am glad you asked and whatever happens, she is fortunate that she has a caring mother.

See doctor: Needs to have a thorough history taken, to include whether the pain is cyclic, or all the time, where it is located, if anything makes it worse or better, any GI or urinary symp. And needs a sonogram to rule out cysts on ovaries. If normal - a trial of birth control pills is often helpful for decreasing (sometimes stopping!) pelvic pain, i would definitely recommend that before considering surgery.