What are some reasons for reoccurring and very painful migraines?

Usually no cause: Quite frequently it is hard to find triggers for migraines. Some causes include tobacco, alcohol esp. Red wine, skipping meals, too much caffeine or skipping caffeine, too much sleep/missing sleep, different smell different periods of menstrual cycle may trigger migraines.

Identify triggers: There are certain foods and aspects of lifestyle that can trigger or worsen headaches and migraines. The best way to identify triggers is to maintain a headache diary and keep a list of foods eaten before your migraine. Common triggers include chocolate, caffeine, cheese, msg, processed meats, alcohol, smoking/being around smoke, stress, skipping meals, lack of sleep or too much sleep.