This morning, I wake up, shrimp out of bed, and commence with the light stretches and joint pops that normally get my body into movement mode in the morning.
Except this morning, it appears I rolled a critical failure on that, because something mysterious and awful happened to my upper back in the process.
The muscles in the left side of my back/neck are all super stiff and not all all comfortable. I have a substantially limited range of motion for turning my head to the left. Lying on my stomach and poking around in the area, it feels like my left shoulder blade is protruding noticeably.
All of these things have happened to me before, with almost-as-mysterious of origins. Back in the fall, I got ran into a wall while sparring at my karate club, and the same muscles on the same left side of my back all seized up. Protruding shoulder blade and everything. It took me a couple days and two or three intense back massages before things were working alright again.
Can anyone with a better knowledge of human anatomy tell me a) what the hell happened to me and b) what I can do to fix it?

Could be a number of things, honestly I suggest chiropractic if you can't find a good diagnosis from your regular doctor. You might have a pinched nerve that you're sleeping on sometimes or that takes a beating sometimes. Before my chiropractic if I shot in and hit just wrong my left arm would go completely numb and seize up...

The exact same thing has happened to me many times. I tried chiropractic, massage, acupuncture (yes, i know it's BS, but I was desperate), stretching, hot soaking, tiger balm, and even muscle relaxers at one point.

The solution: a tempur-pedic style foam pillow. I kid you not. I haven't had a single problem since switching my pillow.

For about 100 bucks the pillow isn't cheap, but it's cheaper than a few chiro visits.

I hope you get better soon. Keep us updated.