Just curious if anybody has cursory experience with what I will describe.
I have never had any serious or notable shoulder injuries that I can recall.
I notice this mostly when I am sitting relaxed, and exhale. The muscles in my shoulder relax and then I feel...not a tingling sensation like a muscle falling asleep, but a sort of...crackly sensation? Not really electric like a pinched nerve, I don't think, but close. The sensation is on both sides of my armpit, like where the pec meets the pit and then the meaty lat on the back of the armpit. I can occasionally feel the similar sensation when I do certain exercises.
I am rather flexible and have found no way to engage or stretch out the sensation other than when I breathe out. It is only in one shoulder. Is it just a lightly pinched nerve? Very curious.