Did your vet x-ray his neck ? if not I would get that done ASAP. IF all checks out OK there you could find a Chiropractor to take him to. Also the K-laser is very helpful for spinal injuries.
www.klaserusa.com you can find a Dr in your area who has a K-laser if you go to the site.
You can go to the YT library & look up VOM=Veterinary Orthopedic Manipulation, this is what my Chiropractor does to my pups & is absolutely Wonderful.