He was lying on the belt under the Jaw crusher to tighten the toggle springs. He set the tools down to roll over to the other side. He noticed a pain in his back as he rolled over. He finished the shift. He reported to work at our asphalt plant on 5-21, 5-22, and 5-24. On 5-25-10 He said that he was experiencing back pain and was unable to perform his regular work.