Muscle Pull Q

Okay.. I know this is a bit stupid sounding.. But... Is it just Meeee??  Now I know that lactic acid burn starts in usually the day after exercise.  BUT.. sometimes a day or TWO later, after a workout.. I'll be minding my own business.. like yesterday.. SITTING ON THE COUCH 😮 and get a Huge Horrible muscle pull in my back.  WTF?  I mean.. I hurry to get in a position to hopefully avoid it being a 4 day issue, and try to put the 'thumper' on it or get the BF to rub it out.. but... geesh.. Anyone else??