3 day after surgery to repair complete torn pec tendon 5cm retract how long b4 pain subsides and i'm unsure if i am supporting arm in sling properly ?

U need to talk it --: over with your surgeon, as all of us have our own postop routines that we follow. Your surgeon is the only one who knows the type of repair, the quality of your tissues, and the repair he obtained. Anyway 3 days is too short a time that pain should subside. Generally pain from the incision itself will last for a minimum of 2 weeks or so. Good Luck.