6 yr old with stiff/cricked neck

[PJM18]

Hi. My 6 yr old woke up yesterday crying and saying the back of his neck was sore. After some calpol and a heat pad he said I felt better and went to school. It was a bit sore last night and a bit better today except if he turns it too far round to the left. I'm not worried about meningitis or anything as he's well otherwise but he seems to be holding his neck a bit funny even though it's not so sore.
Has anyone else had this and how long did it take to get better?

I've had it myself a few times, just poor sleep position. Its very uncomfortable though and all thar helps me is a gentle massage if you could do that for him...