Just of interest, do you stretch before you play? Some people can jump on a kit and rip into to it with no ill effects, whereas others (like me!) have to be a bit more supple before playing for any length of time.
Especially before a gig I spend 5-10 minutes walking around, making sure I stretch my arms, legs, feet, hands, fingers, neck, etc. To be honest I can play without stretching fine, but when I stretch I find things like playing double bass a lot easier.
You may have just strained a muscle or something like that. If it keeps happening go see a doctor but certain things like adjusting your playing position, throne height may help.
Ta.