On 2.20.24, EE was pulling & lifting on an empty battery tray on a CAT 349 Excavator trying to remove it. It did not move, so EE used pry bar to remove. EE reported back soreness the next day but did not want to go to doctor. EE requested to see doctor on 2.24.25 & doctor released to return work. On 2.25.25 doctor required physical therapy and allowed EE to return to work.