Hello guys, I'm 17 and I'm having this problem with my neck. If I am not distracted by anything it starts feeling stiff and uncomfortable, as if my head is too heavy for it. Also I have some sort of really small spasms when I'm trying to sit/stand without moving. The problem guys away if I start to constantly move my arms or legs and I don't even know what that has to do with my neck. Whatever distracts me takes my pain away also. Also, worth mentioning is that I have tried to work out with my neck by lifting some weights up and down with it and I'm not sure if that was good or it was bad. Also I do not always feel this problem, it becomes a problem only when it comes to my mind and when I'm looking people in the eyes. How can I fix it?

PS: I know it wasn't quite  a good order of ideas in the text above but please try to understand.
PPS: it seems as if after some beers the pain fades away.

Thanks in advance!