Ok, so I need some DBR medical advice/explanation/clarification/whatever.

I slept wrong the other night. Apparently I did not move at all during my sleep, or I fell asleep in one position and awoke in a very similar position. When I woke up, I had some serious pains in my hip on the side I was laying all night. I could barely get out of bed the pain because the pain was so bad. I've been limping for two days now.

So, what in the heck caused this? I worked out the morning before I felt the pain, but focused on chest and back so I don't think I hurt myself lifting weights. I've also noticed this type of pain before the other night.

What is causing this?
What am I doing wrong?

I guess I'm not very good at sleeping, which reminds me of a Steven Wright line that goes something like: "My girlfriend asked me 'Did you sleep well?' and I replied: 'No, I made a couple of mistakes.'"