I'm in my early 40"s and have injured my neck several times over the years. The worst was about 3 or 4 years back when I dove under a wave while trying to get out of the way of a knee boarder who was coming straight towards me with complete disregard for my safety. I thought I was in deeper water. I was mistaken and dove head first into the bottom. I thought for sure my neck was broken.
My neck hurt for months before I went to the chiropractor. After a few visits, I was starting to feel relief. Now, a few years later, I usually feel ok must of the time, so I would definitely recommend seeing a chiropractor. Hopefully it's just a muscle problem and not something worst.
I second chiropractic.. Never had severe wiplash but I had several problems (from work and sports injuries) before I started going over a year ago. Now, I have almost no pain and don't have to go very often. Like others have said stretching and yoga exercises I'm sure would be beneficial too.