Hi Paul,
Like a sprained ankle it eventually heal itself. I think I had some anti inflammatory from the Doctor but cant remember for sure but, that sounds about right but I did have it for over 9 months as I thought it would "sort it's self out" I was wrong.
I know now is a scary time to be visiting the Dr's and may of us don't want to waist there time with something we think is trivial, there are other people out there who's need are more urgent. This condition is cause by a slipped disk in your neck that is not trivial. You should get it checked out. There is no way you can judge how sever your condition by yourself.
Worst case scenario for this is a truly frightening and highly invasive surgical procedure. Best case some aspirin and attention to your posture. You mention playing guitar we all pick up bad habits look at your self in the mirror and see if you can improve your posture. If your head is tilted down to look at the strings for a prolonged period this can place pressure on the slipped disk, adopting an awareness of the activities which cause additional pressure on your neck can help to increase recovery time.
I hope it all works out fine for you but go see a Doctor.