Hello.....
I'm so sorry to hear you are suffering from really bad migraines. I hope you feel better soon!
I also suffer from migraines. I take Immitrex to help. Some of the symptoms you are describing I have also experienced, such as, light and noise sensitivity and pain behind or around one eye. The med and laying down in a dark room without noise is the only thing that helped me until I looked into it more. Prior to the that I never suffered with migraines or headaches. It began suddenly 5 years ago. I saw many different specialist and a neurologist at first thought I could have MS because of a few other unexplauned symptoms in combination.
After researching online I also learned it could be related to my sinuses. I began suffering with chronic sinusitis. I saw a ENT and he did a CT scan and noticed I had a deviated septuem which just so happens to be on the same area I would get migraines around my eye. I agreed to have surgery to fix the deviated septum, sinoplasty, tonsils and adenoids removed too. I can't begin to tell you a world of difference it made. Before surgery I was having a migraine almost every day and couldn't take the Immitrex as often as I was having them. After the sinus surgery, I may get a migraine once a month or every other month. I also had a allergy test done to see by chance if allergies could be playing a role. At first the test came back saying I was allergic to just about everything, including a food allergy. That didn't make any sense to me because the food the test said I was allergic to I eat all of the time. The doctor said it was a false positive test. You also mentioned having other stmptoms like when eating chocolate and having GI problems. This sounds like it could be a fungal infection in your GI. I can't remember the name of it iff the top of my head. I also researched this infection and looked at it being possibility. In combination with all your symptoms it tells me it could be this, but it could also be seperate and you may have sinus issues like I had and your GI may be seperate and not related. I hope some of this info helps you and hope you feel better very soon!

Best wishes,

Diamond Tiger<3