most people have some kind of tightness in their neck muscles and since cervical spine injuries can influence almost the entire body, that might affect different parts of the body like the digestive system, the reproductive system, immune system and etc. in order to correct the tightness on one side, all you need to do is strengthen the muscles on the opposing side. the neck is really vulnerable and can get hurt really easily so avoid any fast repetitions, extreme range of motion, and using heavy resistance.