I noticed when I started to exercise more seriously few years ago, all the pain from working 8h+ in front of a PC magically disappeared. But I think the key isn't just do the exercises for a good posture. Just commit to something a little more ( gym, tai chi, whatever you want ) and your body automagically will handle better the "bad habits".

TLDR: I noticed a lot of difference between just doing postural work and a fully committed "sport".