I, unfortunately, cannot help you with more information on some "database", but I am so sorry you went through that experience. I also experience Migraines and it seems as though some docs understand and empathize, others think it is "in your head" (no pun intended--ha ha!) It is a real matter of luck as to what kind of care you will receive. Please keep all of us up to date on what other information you find out throughout this experience. I just cannot imagine that with HIPPA they (multiple doctors) could share your health related information ethically or legally.
Best of luck...hope you do not have another Migraine for a long time!