Hi Karen,
I began having neck pain just about 2 months ago; my surgery was in July of 2010. It is only on the AN side; posterior to the mastoid bone and extending downward. It feels like the muscle is just about to cramp up, but it doesn't. It doesn't always bother me, and since it is relatively new I can't identify when it happens more. I have chalked it up to the effects of surgery on the body. I am surethat the surgeons cut through muscles back there in the process of removing the tumor. From experience I know that the muscles are just never the same afterwards. In 2005 I had a modified radical neck disection (removal of all lymph nodes on one side of neck) and a thyroidectomy for thyroid cancer. There was much nerve damage in the neck so I don't really feel much; but those muscles cramp like crazy when I am tired and move my neck a certain way. Kind of a really weird sensation to have a "charley horse" of the neck! Thiese symptoms have not changed one bit in the 6 years since that surgery. I thought it was temporary but it seems to be the new normal for my bod. Happy to not have thyroid cancer; glad to have a smaller acoustic neuroma after surgery... but there certainly are lots of unexpected little changes to adjust to aren't there?
So I don't know if your sensations are similar to mine but I wanted you to know that you are not alone!
Suz