Awehib, I'm about 5'8 and 140, and the medium is a little long on me. I bought my girlfriend a small shirt, and tried it on. The length was okay, but it was pretty tight on my shoulders/chest. I do have fairly large/broad shoulders for my size, so you may be okay with a small. If you like your shirts fairly short and not too baggy, go small. If you like them a little long and loose, go medium.
Left my cloud tee at a condo I was staying in at the beach... so mad.
Well I like my shirts to go little below the belt loops of my jeans. So I guess I'll go medium?