1. Stress is the most common trigger of a headache.
2. Suggestion- keep a migraine diary to see what has triggered it – weather, food, stress etc
3. Lack of food or sleep
4. Bright light or noise
5. Hormone and weather changes
6. Chocolate alcohol, nicotine
7. Some foods, and food additives such as MSG

One theory about the cause of migraine is the blood flow theory, which focuses on blood vessel activity in the brain. Blood vessels either narrow or expand. Narrowing can constrict blood flow, causing problems with sight or dizziness. When the blood vessels expand, they press on nerves nearby, which causes pain. 

Another theory focuses on chemical changes in the brain. When chemicals in the brain that send messages from one cell to another, including the messages to blood vessels to get narrow or expand, are interrupted, migraines can occur. 

1. Migraines are intense, debilitating episodes of intense headache pain caused by the expansion and contraction of blood vessels in the head and neck area.
2. Some foods commonly seen as migraine triggers are chocolate, red wine, cheese and foods using nitrites as a preservative such as hot dogs and bologna.
3. Hypoglycemia or low blood sugar may also cause migraines

The following foods and drinks are known to precipitate migraine attacks in some people (a minority of sufferers):

1. Cheese (especially matured cheeses; cottage cheese and cream cheese tend to be all right)
2. Oranges and other citrus fruits 
3. Alcohol, especially red wine, brandy, and whisky
4. Chocolate
5. Vinegar and pickled foods
6. Smoked foods
7. Sour cream and yogurt (some people are sensitive to all dairy products)
8. Nuts
9. Yeast
10. Wheat
11. Onions
12. Bananas
13. Pork
14. Caffeine (found in tea, coffee, cola drinks, and chocolate)
15. Avocado
16. Foods containing nitrites and nitrates (such as hot dogs, salami)
17. Foods containing monosodium glutamate (avoid all processed foods unless you're sure they do not contain it — it gets into almost everything!)

"A recent survey of 30 managed care plans showed nearly 70 percent of prescriptions written for patients with headaches are for narcotics. ... Specialists are now sounding the alarm. Narcotics, they said, are an unproven and risky treatment for headaches and should rarely be used. ... Dr. Stephen Silberstein, president of the American Headache Society at Thomas Jefferson University Hospital in Philadelphia, said long-term use of narcotics can actually magnify headache pain and could render other treatments ineffective. 'Not only does it deplenish your own natural painkillers,' he said, 'but it destroys parts of the brain that are responsible for fighting pain.' Narcotics bring other risks. They can cause hormonal changes and intense physical dependency. Still, many pain-management specialists insisted there were many headache patients who, if carefully selected, will do well on narcotics -- patients for whom no other drugs worked." Source: ABC News