Out of the blue

The only thing I can think is that I slept on it wrong. I used to sleep with my head laying on my arm with my arm going almost straight up over my head. Then Dr. Barr told me that that was very wrong and for me to at least stick my arm out at a 90° angle from my body. I have rarely done it the wrong way since she told me.
But I think I did it wrong the other night again.   All day yesterday, while we visited the Virginia  War Museum my arm hurt. Today I happened to have my follow-up for my neck epidural I got a few weeks ago. I told them what I was feeling.
They said my collarbone had popped out! OMG! No wonder it was hurting! I knew it was something I’d never had before!
They were able to fix it back and I’m really sore and waiting for my Celebrex to kick in, but it’s all good. I have learned my lesson!