EE was tightening a nut on a D3 EE was operating with pliers, both hands using full grip. EE said EE's chest popped & EE let go & drove ride outside & reported to another EE. EE did not see a M.D. until 7 days later, 11/27/17. EE missed 1 day of work, 11/28/17 and returned to EE's normal job 11/29/17.