Pulled hydraulic oil hose until reel locked-made swinging motion to toss hose on top of excavator. Felt twinge in upper left arm. EE got on excavator to loosen fill cap with wrench. Cap was screwed tight-so EE pulled on the wrench with both hands-felt another twinge. EE used different wrench, was able to loosen fill cap. On 10/4, EE requested to be checked by doctor.