Lifting Piggy Back What Did I Do To My Back?

What did i do to my back? - lifting piggy back

I was moving things into the yard / room for 2 days (AC's, TV, sofa-beds such things ..). He pulled the keys to the burn pile and / or containers.

Then I went home to take care of my cousins and play with the baby was hard enough. I climbed into the pool, then gave piggyback rides around the yard, then fight for a while. We have a party, where the charges and I can block him. I then used a slide when I sat on the floor beside the sofa. Then he jumped on me and used as a springboard.

Well, today at work, my back began to hurt to do. that was so bad that even a lift quart of milk, that I felt like my shoulder will be removed from the socket. and move your neck horribly wrong, like any elevator. What is possible? Pain is usually right at the base of my neck, upper back and shoulders. It feels like theres a knot or something.