S.S.
I second both the chiro and acupuncture. I had amazing results with acupuncture (having never tried it before) when I was looking for natural relief for severe seasonal allergies when pregnant with my 3rd child. So I totally believe in it now!
Also, while you are trying to figure this out, maybe look into getting a Baltic amber necklace to reduce the intensity and frequency of your migraines and so you don't have to resort to so many meds. Baltic amber is a resin which contains succinic acid which is a natural pain killer & anti inflammatory. The heat from your skin warms up the amber which allows it to releases it's oils into your skin and bloodstream. it works really quite well. I wear mine for headaches and get very good relief. I know of several people who suffer from migraines who say it really reduces how often they get one and that when they do get one, it is more mild. You can learn more about Baltic amber and how it works at www.hazelaid.com
You have to make sure the amber is from the Baltic region and is not set in a metal setting because it needs to touch your skin to be effective. Amber from other regions does not contain the same amount of succinic acid and is not likely to help with pain in the same way. Good luck on your quest for health! Good for you for wanting to find the root cause and not just placate the symptoms!