That was one of the first symptoms of my chronic fatigue. That and hypoglycemia, which I now realize is a side effect of adrenal fatigue. It's not a constant thing anymore, though. When I first had the problem, I found that if I stopped eating wheat, the stiff neck would go away, and off and on I don't eat any grains. But now I am back to eating only sprouted grains, which don't seem to cause too many symptoms. Not too long ago, I realized that if you have Lyme disease, cutting out gluten will clear out some of the symptoms. So I am not sure if the stiff neck was totally an adrenal, gluten, or Lyme problem. I do know, though, that it is a pain in the neck. Traditional Chinese Medicine says that stiff neck and shoulders are caused by liver stagnation, if that is any help.