I also experience this buzzing during waking moments. It seems to center around my upper chest/abdomen and mostly only happens after I’ve been asleep but not yet fully awake. It is a very alarming sensation, usually it occurs for 3 seconds and stops, then 3 seconds again and stops, this pattern repeats until I choose to wake up or fall back asleep fully. I as well experience a noise when closing my eyes harder than normal, a user above referenced, but that has always happened while awake. I’ve seen multiple doctors and was referred to a neurologist who was very hateful and not helpful, and that’s where my journey ended. This didn’t occur prior to contracting Covid however I don’t know if it’s related. I’ve read both articles regarding Brain Zaps and Sleep Myoclonus and neither of these point to my experience. I would love to know the cause and how to treat.