EE WAS LOADING TRUCKS FROM UPPER STOCKYARD WITH WA500 KOMATSU ENDLOADER. HE STATED THAT HE FIRST NOTICED PAIN AND STIFFNESS IN THE BASE OF HIS NECK AT APPROX. 10:30 AM HE STATED THAT HE CONTIN UED TO EXPIERIENCE PAIN THROUGHOUT THE SHIFT. THIS INJURY WAS NOT REPORTED TO THE SHIFT SUPERVISOR UNTIL 2:55 PM.