After spending the weekend worrying about what was going on in my neck, I was quickly reassured by my doctor of two things: the pain in my neck isn't psychosomatic, and what's going on in there can be treated and, with luck, easily resolved.
He termed it a "disc protrusion," with the formal diagnosis of cervical radiculitis. This is a less serious dysfunction than a slipped or herniated disc, and physical therapy was prescribed.
There must be something wrong with me that I need physical therapy so often, as if my body can't keep itself in order. This is an idea I am willing to leave unexplored, since everything that's gone wrong so far has been fixable.