Can't decide between a S or XS…Need help! 150ish lbs, 5'7. Can't stand long shirts so XS length looks good, but want to make sure I have room in the chest. I can do a 20" chest all day in lighter stuff...
I'm around your size and I would go with S. Length hasn't been an issue for me (although I do wish some of them S shirts were a tad shorter, it would result in a slightly cleaner look.).
I can't do the shoulders in XS but then again I have broad shoulders for my frame and work out.