I notice that twice you referred. I believe, to “needing rest”; or once that you felt tired and wanted to lie down, but didn’t know if in either case you would fall into “a deep sleep”. You wisely seem acutely aware of “resting” which does not necessarily mean “sleeping”. You could be mowing a lawn (not motorized), for 1/2 an hour and decide you need to rest. You need a break. But you realize that a restorative “deep sleep” is what you are seeking. No doctor, I take the lazy man’s approach and Google “can insufficient sleep cause chest pain”? What d’ya know. Several articles, not all AI, assert so. Always consider the source of the info and ask yourself what they’re selling, of course. Still it seems that a “rest sleep” won’t bring you down to the REM state when our bodies do a make-over and damage repair if any. We hear a lot about sleep hygiene. I’d have to deprive myself to be hygienic, and I think sleeping pills aren’t natural. You seem like a young, no-lying-around man. About the
chest issues. at least consider a quick Google. Even “rest vs deep sleep” yields opinions. Good luck to you, and consider the source. 💤. 🛏️