you might want to take her to the doctor what side is of her stomach is the pain on because she might have appendicitis and that is extremely serious and you should take her to the doctor because if its is and yo dont take her IMMEDIATELY then her appendix could EXPLODE and she could DIE IM NOT EXAGGERATING!!!!!!!!!!!
take her to a gyn. she could have not fully matured ovaries and or fallopian tubes which are causing pain or there could be blockage. which may cause the pain> make sure she does not have a slight fever.