Answer
Answer 21-7. It has no warning. Migraine headache is usually moderate to severe intensity, usually pounding, often unilateral and usually accompanied by nausea, vomiting, light and sound sensitivity. It is worse with exertion, and usually lasts several hours up to a couple of days. The headache may be provoked by food, drink, stress, erratic schedules, lights/glare, smells, part of menstrual cycle, etc.