There are so many reasons for headaches, migraines. I hope you are seeing a neurologist. If he can't help you might try a pain clinic.
One possible reason for migraines is food intolerance, especially foods containing sulfites. http://www.learningtarget.com/nosulfites/index.htm
There are many, many posts you can look up easily on the forums here. Just put a couple of keywords in the search box at the top of the page.