Both my chiropractor and a trainer have told me that I am very tight in my upper chest which negatively affects my posture. While they gave me exercises to do to correct this (leaning forward in a doorway to stretch my chest muscles is the main thing) I'd like to do something a little more regular to help with this. I've seen a lot of elastic braces and other products that promise to help strengthen the muscles that affect posture. Has anyone tried them and do they actually work?