Migrain is a primary (unknown etiology) non life threatening recurrent headache that's more common in females. It's symptoms are throbbing type headache involving one side of the head. Other symptoms include sensitivity to light, nausea and vomiting... in some people it's preceded by something called aura(warning of impending attack) which is characterized by visual disturbance. The headache is usually worsened by physical activity. Hence people with this headache prefer to sit in a dark quiet room on occurrence of the attack.