Why Do My Nerve Endings "buzz" Like Electrical Current Is

Why do my nerve endings "buzz" like electrical current is rushing through them? It's usually accompanied by a sound that momentarily blocks my hearing. Tonight while working, it even caused the room to go sideways. This has been happening for years, but only for a few hours at a time. Then it goes away and may stay gone for months at a time. So I never gave it much thought. This particular episode has been going on for almost a week, and I've had a miserable headache for at least 4 days.

I've come up with 3 possible theories, but I'd like to hear what the experts have to say first.

Thanks!!! Maggie Gardner