A freak mishap

[countrymon50]

I was cleaning my room and was putting things on a shell i was standing on a stool and it buckled on me. After this I felt a sharp pain in my back lasted about a second, but the way it happened I should not have felt such a pain was like a needle or a knife piercing me.   Not sure about this if it was my back or a exoophtic kidney cyst on the right side errupting suddenly.  So not sure where to ask about this. I left a note with my PCP but wont hear till Monday. Any ideas about this would help,