Somewhat sceptical of the benefits of chiropractic myself. I certainly would not let them anywhere near upper spine/neck area - I have read several instances where such practice has caused the patient serious harm.
The foundation of chiropractic is a belief that spinal misalignment and subluxations are the cause of pretty much every disease. Some of the more sensible chiropractors have disavowed this, but quite a few still believe.
http://www.sciencebasedmedicine.org/index.php/the-end-of-chiropractic/
From the article
"When chiropractors use spinal manipulation therapy for symptomatic relief of mechanical low back pain, they are employing an evidence-based method also used by physical therapists, doctors of osteopathy, and others. When they do “chiropractic adjustments” to correct a “subluxation” for other conditions, especially for non-musculoskeletal conditions or “health maintenance,” they are employing a non-scientific belief system that is no longer viable."