I have a fitting issue that I can't find in fitting books. If I'm wearing an open jacket or cardigan, the back swings out, so if you were to look at me from the side, the back of the garment, at the hem, sits way away from my body. The shoulders seams are right across the top of my shoulder, I don't find that they ride to the back or the front.
The side seams on my garment don't hang straight up/down, they ride angle towards the back at the hem.
I've read a bit about forward shoulder, and rounded back, and these don't seem to be quite what my issue is, or at least that's what I think. I do think my posture could use some improvement, my opinion is that my shoulders/back are slightly rounded.
What kind of adjustment might improve the way garments, especially jackets/cardigans hang on me?
P.S. Related to this, I really want to work on my posture, can anyone point me to web sites with good exercises/techniques?