Silly kids, sleep paralysis.

That's not a demon sitting on your chest. If you meditate long enough you'd know that eventually your body goes to "sleep" and the heavy feeling is much like a lead blanket.

It is the precursor to an obe. Sure you might've been spooked by an etheric entity or two but believe me ain't shit to be worried about.

Stay in this state long enough and you WILL have an OBE.

Enjoy.