I used to have episodes of sleep paralysis like you describe, also with the buzzing sound and an intense vibration feeling. That was before I had MG, though. The reason I had sleep paralysis back then was that I was sleep-deprived because I had babies. I would have an episode of sleep paralysis when my body was exhausted but my mind was telling me I should wake up. That makes sense. My mind was awake, but my body was asleep.

I don't know if everyone's experience is like mine, but you should see if getting more sleep helps--or, if you can't get more sleep, at least journal your episodes in the hopes of finding out what triggers them.

Abby