This is an interesting question. I've found doctors who are general practitioners usually to be very poor at dealing with sports related injuries and things such as neck pain. In my experience, they mostly just prescribe pain killers and rest.
Chiropractors can give almost instant relief to some neck pain. I've experienced it myself. It definitely isn't a placebo effect, but I'm not sure if it is actually dealing with the problem or simply affecting the nerve impulses temporarily. Getting adjusted once rarely is going to cure a problem. I expect chiropractors these days to be physical therapists who prescribe exercises and stretching. Cracking the bones isn't a permanent fix for anything, and doesn't necessarily heal damaged muscles, tendons and ligaments.
In either case, I look for someone who is willing to take the time to try to properly diagnose the problem and is willing to suggest changes to what may have caused the injury and exercises as part of the treatment.