K.M.
I think I would take her to a neurologist to get to the bottom of the headaches (and rule out anything awful). I would also try to really modify and manage her diet, are there food triggers for the headaches and behavior? If neither of these things help, I might see what some Eastern Medicine can do to help--accupuncture, craniosacral therapy etc... Good luck-- how scary and awful to watch your child go through such a personality transformation. I hope you can get to the bottom of it.