What I have found & learned over the years..

If you work at a desk you must work to negate the forward head/shoulder postures.

Do opposite postures often during the day.
Lay on the floor in the corpse pose - http://images.google.com/images?q=co...N&hl=en&tab=wi
as often as you can and for relaxation and use diaphragm breathing

possible hypertrophy of neck, back or ?? muscles?
Muscle imbalances pulling on the vertebra?

I would get a full evaluation with a expert PT or expert chiropractor to really find out how your spinal alignment is & they can do some tests to find out if it might be something spine related or soft tissue.

our useful sticky has even more saved info and videos therapy etc.-
http://neurotalk.psychcentral.com/thread84.html