My daughter had bone cancer, survived, all is fine now btw. My advise to you is to be careful what you allow yourself to think about...guard against jumping to conclusions and conjuring up worst case scenarios, its human nature, believe me I know.
FWIW, I'm unaware of bone cancer presenting with symptoms which you described. We're all scared for our kids sometimes, be careful what you allow yourself to think about... for your own sanity.
Said a prayer for your daughter,
Jon