EE was lifting a cross-over duct work onto M15 miner. The EE felt pain in his lower back. He finished the shift and worked several days after. On 2/16/09 he went to the doctor and doctor would not release him to return to work. On 2/17/09 this became a lost time ""Reportable"" incident. The EE had tools and equipment that was there to help lift, but chose not to use them.