And something that's just weird

So I have some kind of knot/pinched nerve/sore bit/whatever in my shoulders/neck/back area.

I have a sneaking suspicion my attempt to practice tumbling last night led to said pain.

Last night I had my first martial arts class in about a week. I was expecting to re-enter a world of pain.

Instead, I had full-mobility of my neck and shoulders at the end of the class. I felt great. Tired as hell, but great.

This morning... stiff neck/shoulder again. Not as bad as before, but worthy of a snivel or six.

This makes no sense to me.

Time for more Advil.