I would definitely get this checked out, I think a couple of things could contribute to such a problem. Raynauds is one of the possible answers, but I think other issues could be causing this as well.
If your rheumy or PCP isn't much help, get a referral to a podietrist. Well, I'd get one anyway to get a second opinion on it to be sure. If bad mechanics are causing it, then they would be the person to help you out anyway
Good luck. **