I am having these issues, also. It seems to come inevitably when playing a male elf, regardless of your class.
The first armour you wear in the game -- as in, when you start a new game, design your character, and then play through the prologue right up until you wake up in Haven, didn't cause me any problems. My elf was properly proportioned and he didn't have strange looking arms.
Then, when I started equipping new armor, the bug became evident. It was its worst when I came to Val Royeaux, they seemed to just stay static by his side while his torso and chest moved independently.
I took some screenshots to compare Solas' body shape and his apparent lack of the arm bug, against my Inquisitor. It isn't a problem with his body type, per se, it's to do with proportions (which seem to change all the time), and the arms looking really really strange and tend to clip a lot.
The first screenshot may just be a design choice, but having the arms clip *through* the body, remain stationary as the rest of the body moves, having proportions change noticably depending on which armor is equipped or which screen you're in, as well as the general broken-ness of the arms cannot possibly be by design.
http://i1236.photobucket.com/albums/ff455/fundamentalnail/arms.png
http://i1236.photobucket.com/albums/ff455/fundamentalnail/ScreenshotWin32_0044_Final.png
I've been following the BSN thread on this issue for several weeks now with hopes of news regarding a workaround or even a patch, but with no such luck. So I figured I'd add my voice here where it will hopefully add to the cause.