Were you experiencing any noticeable stress before or during the onset of this issue?

Neck and throat issues are pretty classic symptoms of stress/fatigue/grief. In a lot of people it goes to the gut, others have headaches, and some people are throat and neck.

Or it could be something as mundane as too much lying flat in bed with your head propped forward looking at a screen, too many hours at a desk which is the wrong height, or just general postural issues.

What I do know is that something that seems reasonably small and benign can manifest as a huge problem in another part of the body, and it can take a long time to correctly recognize what the cause is, and often normal medical examinations don't find it because they are looking for more obvious signs in blood work and tissue trauma.

Have a good think if anything in your behavior could be unreasonably stressing that area, eg Is your head alignment consistently in front of your body? Do you sleep in a difficult position? Are you anxious and stressed generally?

Whatever the cause, trying to relax is always going to help.

Best of luck.