I Have Some Discomfort In The Back Of My Neck

I have some discomfort in the back of my neck on the right side when I turn my head to the left. It also makes a popping sound. It has been going on for about 4 months now. I use only one smaller pillow and sleep with my head less elevated but it does not seem to make much difference. Pain is only noticeable when I turn my head to the left