Anybody else suffer from this..It may be more than physiological...

Used to happen to me from time to time when I was a kid. Was decades ago now.

Rarely but yea, feels like an oppression on your chest or in the room and you can't move or talk

They can be a doorway to lucid dreaming, which is sweet.

I've experience this on accident a handful of times. The first time I thought I was having a stroke. Nothing I did could break me out of it. Other times had crazy auditory hallucinations and even had dark figures appear. As I researched it I found a way to fall asleep and induce it. I followed the directions exactly and it worked and put me into sleep paralysis. It was the scariest experience though and I had felt the figures were demonic this time.

Ever since the moment when I was able to induce it myself I have refused to try again.

No, but if I sleep on my stomach my arms fall asleep and it's really hard to move them.