Sometimes when I get a muscle that's stiff and so tight that it feels like it's getting ripped open, the area feels all hot too. I get the hot-related effect a lot on the sides of my neck and the side of my face where my jaw hurts, and those can make my face pink or my ears red too when they're reallllly hurting. Then again, I turn red or pink really easily from smiling or laughing, and my skin feels all warm then too, so I wasn't worried about it.
Anyone else with hotness/redness generally turn red and feel warm for non-scary reasons too?