Recently, I've treated several people with neck and shoulder pain. When I massage a client with these types of complaints I often notice that they hold tightness in their chin and lower lip. Out of curiosity I've mimicked this action and discovered that my neck gets tight as a reaction. That's only natural considering how many muscles are in the chin.
When I'm treating someone's neck, and I see them holding their chin, I find their hyoid bone and gently move it back and forth. Since so many of these muscles attach and originate on the hyoid bone, with my client's permission, I gently place my fingers on either side and move it back and forth to create softness in these muscles. Usually by the end if the session, people are relaxing their chins and even smiling. I believe that after these 60 minute neck and shoulder sessions, many of my clients are more aware of tightness they hold in their chins and can soften it with ease.