9. Brain malfunction: Migraine could be a result of brain malfunction that may involve neurotransmitters (brain chemicals) such as serotonin. The cyclic changes in the secretion of these chemicals may lead to pain and migraine.
10. Constriction and dilation of blood vessels: A spasm or constriction (narrowing) of blood vessels in the neck and head followed by dilation of the blood vessels minutes to hours later may cause migraine. The dilation may increase the pressure inside the skull, resulting in headaches.