Body pain

So i've been thinking, I recently fell on ice and even for a 20 year old am very sore. As i laid in bed last night, unable to movce, i wondered, when things on your body are hurt do you want to favor them because you know you can't lay on that side, or because you normally do?
Let me elaborate. I know for a fact I usually fall asleep on my right side, but since my left is hurt i was dying to lay on that last night. Was it because i mentally knew i couldn't without pain, or was it because when i'm asleep i roll on that side?
It's kind of like when your throat hurts and you realize how much you swallow, is it becasue you always do that much or because you realize it more while it hurts?
Any suggestions.

Through my fall i still find things that are simply amazing. As you all know about my mother, you know we are crazy fools with head injuries. During my fall i hit my head, and there happened to be a mat not where it was supposed to be and off to the side, being exactly where my head hit, instead of the cement step. Thank God!