Glad to hear so much has been ruled out. rnlorena posted an interesting plan she will be seeking. Yes, sometimes one must travel far to find medical answers no one seems to know in your location.
Remember, there are many, many neurological disorders...some most people have never even heard of. You might fall into this category. The CSF leak usually presents as no "headache/pressure" when lying down. Upon rising, the pain does not start immediately, but will come. I also had pressure on my temple and front of my head and my neurologist thought of a CSF leak which I did not have. Also, remember there are many "types" of migraines. If I were you, I would look at US News & World Report for 2025 medical center rankings. Look at who is #1 in the country for neurology. That's exactly where I would go for another opinion.
Regardless of the distance...the very best of luck to you.