Employee stated on 8/03/06 that he had pulled a muscle in his lower back while tightening lug nuts on a truck tire. He notified company of the alleged incident after receiving pay minus a previous pay advance which the company paid because he was considered a voluntary quit. His 1st Dr release for ""illness"" from 7/25 thru 7/29; 2nd release from 08/03 thru 8/07 ""no remarks"".