A question I am asked at least once a week and more likely once a day.
IMHO: At one time more than 10% of the UK’s population suffer from headaches and they are one of the main reason for seeking advice from a GP. Over 90% of all headaches are primary headaches – this includes all tension-type, migraine, cervicogenic and cluster headaches. Primary headcahes have no other underlying medical condition to cause them - so, if you have a headache is is very unlikely to have a serious medical condition as the cause.
In a report published in 2001 by researchers at the ‘Duke University Evidence-Based Practice Center’ in the USA they found that spinal manipulation resulted in almost immediate improvement for those headaches that originate in the neck, and had this form of treatment had significantly fewer side effects and longer-lasting relief of tension-type headache than a commonly prescribed medication.
We've certainly had real success here in C1 Chiropractic Health Clinc with these headaches and give us a ring if you want to know more.
And, I suspect there is more - far more, out there and I'll try and find it and add it as I see it.
C1CHC
Pro 
A second major spine care review was published in 2008. It is the report by the Bone and Joint Decade 2000 – 2010 Task Force on Neck Pain and its Associated Disorders and built on the Quebec Task Force on Whiplash. This report follows seven years of literature review and original research from more than 50 researchers and the editor of Spine described it as a “milestone”.
The report covers all aspects of neck pain, including headaches, arm-pain and other neck generated symptoms. Tellingly, it states that neck pain is a “multi-factorial and episodic or recurring problem”. It adds that because patients have many differing personal factors underlying their problems best management requires informing and educating patients on their options and respecting their preferences.
The report suggests a grading of neck pain into grade 1 (little or no interference with daily life), Grade 2 (limits daily activity), grade 3 (with radiculopathy) and grade 4 (with serious pathology).
It then goes on to add that most patients have grade 1 or 2 neck pain and that treatments, with similar evidence of safety and effectiveness, are education, exercise, mobilization, manipulation, acupuncture, analgesics, massage and low-level laser therapy.
Treatments NOT supported by the evidence are surgery, collars, ultrasound, electrical muscles stimulation, TENS, most injection therapies including cosrticosteriod injections for the cervical joints.
So, for most of us, if you have neck pain see a spinal health expert, such as those at C1 Chiropractic Health Centre and not a surgeon.