If you can't turn you most likely have strained your neck. If this just happened, you probably had your head in one position too long, maybe turned quick, or took an injury to the neck.
The best thing to do is to ice if it's inflamed. You'll know this if it's raised, hot or red even. Typically at the end of day inflammation might be more.
Heat in the morning or a hot shower soaking on the area may help. Other things that may help are massage and gentle stretches.
The big one is using your neck pillow. This will help alignment which is the big thing. Aligning the neck takes pressure off of nerves which will ultimately get you better.
Additional Reading
- Being Ability to Move Your Neck Side to Side Up and Down is Key
- A Pillow to Help with Neck Pain and Moving Around
- Exercises to Help a Neck Posture that is Forward
- The HunchBack Posture
- The Neck Pain Pain Relief Shop
