Try keeping a diary of your back and neck pain and your Migraines. Neck pain can be a symptom of a Migraine. I can't diagnose, but when triptans such as Axert relieve neck pain, it's usually because the neck pain was part of the Migraine.
If you haven't already, please bring up this subject with your doctor. You're right that it might be helpful in diagnosing your neck pain.
Good luck,
Teri