Why arm no werk?

Music: Penny Arcade podcast

So, this will be a short post as typing is no good right now for reasons I am about to explain.
Somehow this morning I managed to dislocate my own shoulder.. yes, that's right. Dislocated my own shoulder. Now, it's not like it came out and then someone had to come over and force it back in or anything. It popped back in by itself, sat down in the back for a bit (I was at work) and then went home. The stupiddest thng about all this is what happened to cause this.. I was stretching because my arm and shoulder and back were all sore because i had slept on them weird (due to going to sleep drunk on wednesday), just trying to stretch my arm out a bit, then all of a sudden there was a sickening pop, my arm lengthened a bit, and the whole arm rotated ninety degrees at the shoulder.
Then it went back in and everything was very painful for the next while.

Although if my shoulder hadn't popped back in by itself, I am pretty sure I know how to do it and could either explain to someone or do it myself. I think..

I have never actually had to try it...