I’ve had this issue too. Always wore large, now they’re too short. I’ve had friends take little jabs, cause I’m a little bit heavier than I was, but that hasn’t elongated my torso or spine. My middle didn’t get longer, and I don’t think my shoulders are 3-4" more beefy than they were. Now, I get a Large and it fits like I expect for a wear or two, and then it’s immediately a medium. It sucks, cause I don’t buy clothes often, so I’ll go to a sporting event and get a shirt, buy a L, and then it shrinks to unwearable size.