My 16 yr old daughter has been having symptoms severe head pain , vision changes , hearing changes ,dizziness, feeling faint , balance problems could it be a brain tumor ? she did have a ct scan but it didnt show anything?

Not clear why you ponder a "brain tumor" with a reassuringly normal CAT scan. More likely, the reported symptoms are consistent with migraine events, and you are advised to seek consultation with a pediatric neurologist ASAP. All of this can potentially be controlled and reversed.

Please see a Neurologist, have a migraine treatment plan, keep your daughter well hydrated. Monitor temperature and breathing. Her balance problem requires attention and a stroke should be ruled out.