I actually just read an article about this but cannot for the life of me find it. I do, however, remember reading that one cause is likely a weak pelvic floor and/or core. There were tips and exercises to strengthen both (and yes, it included kegels). I can vouch for the fact that I experience this pain more when I have been neglecting my abs. The stronger my core the less pain. If I find the article, I will try to post it. Not saying that this is the fix for what your daughter is experiencing but working on strengthening both shouldn't hurt and its free...