You might want to read about chiropractic and the C1 -C 2 alignment also called the atlas and axis or upper cervical adjustment.

Could possibly be the vertebral artery getting affected by misalignments in the c spine.

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