Yeah the bindings angles aren't bad, although duck isn't for everyone. You could try a neutral (0/+18 or so) or forward (+10/+30) stance and see if it improves.
for a 5'7" person I'd try reference stance width on most boards. Something around 21" centre to centre of the bindings.
You may need to go to a sports physiotherapist. Bring your board, boots and bindings and maybe they can help???