I've thought for a long time now that everyone has a migraine all the time, but migraine sufferers temporarily lack the brain's ability to ignore the ever-present pain.
In other words, the migraine isn't the addition of pain, but the absense of a pain relief mechanism. I have no sources to back this up, other than personal observation.
I got told that it could be indeed the case that my brain continuously has small seizures but only from time to time they break trough and cause the pain and auras which I would then experience. They wanted to measure the brainwaves to figure out if that was the case. That would also somehow fit what OP said, so I guess this is known in the medical world already. Or at least something in that direction.
Only that's not how auras seem to work. The current understanding is that they are caused by cortical spreading depression - a slow travelling wave which depolarizes the brain cells it passes through. These don't just happen randomly in healthy controls.
Well, I think the Auras is my brain failing to filter out visual noise, which then get's into a feedback loop and builds up. And that might be related to other filter functions failing. I think that, becaus4 once in a while, I'm able to suppress the Aura conciously, when it is still very small.
Some auras have a musculo-skeletal origin. For example, some neck issue irritates a nerve or alters the pressure in a blood vessel, which in turn affects the optic nerve.
I have suffered them myself, and they always came in a sequence: arm pain, neck pain, headache and aura. Finally, I'd release tension in my neck and it'd be gone.
My doctor confirmed injuries in cervical discs also seem to be causally linked to auras, but there might be other causes as well.
The pounding pain that corresponds with heartbeat. It makes me think there are nerves that register this all the time but there's some part of the nervous system that filters that signal out.
If you have pounding pain from heartbeat, you should go see a doctor. That is not normal.
One feature of migraines is not just a headache. Some people can feel it coming, called the aura. I feel weird during and after the headache. I frequently get the migraine weird feeling without the headache, so-called silent migraine. Migraines and normal headaches feel different.
In other words, the migraine isn't the addition of pain, but the absense of a pain relief mechanism. I have no sources to back this up, other than personal observation.