my back hurts

Yesterday I asked Maddie to pick her books up off the floor and put them on the chair. She responded with, "I can't do it. My back hurts," as she placed her hand on her back. "Maddie, you need to pick your books up and put them on the chair." She bent down to pick up a book and froze with her hand still on her back--"Oh no! I can't do it. It hurts my back!"