I think I would follow up on the neck part to see if that is a partial reason for the neck pain.
Have you had MRI or xray of the C spine?

I don't know how you feel about chiropractors and I missed the part about the wheelchair- but if it isn't due to a severe spine injury- a good/expert DC might be of some help.

info links-
Chiropractic care info- a good one can help with many symptoms:
http://www.upcspine.com/self.htm
http://www.uppercervical.org/subpag...b/about_faq.php
http://www.spineuniverse.com/index.html
http://www.coloradochiropractic.org/.../glossary.html