i tore my left pec 80% off the bone.it sounds like you have a muscle tear.mine was the tendon and it didnt hurt at all when it happen.just a god awefull sound that stays with me to this day(its been almost 7yrs now).i did mine with dumbbells.was doing the 140's and they were light so i was kinda throwing them around and then BAM,dumbbell almost fell on my face.scared the shit out of me and my training partner looked like he had seen a ghost.i sat up and could feel the muscle just slide down my chest(sick feeling).i had to have surgery to get it reattached and within 6mnths to a year it was recovered but mentally im still messed up about it.its always in my head now when i do chest,always.anyways good luck and dont push it to hard for awhile.i do alot of fly movements and very rarely do any heavy flat bench anymore.no more ego trips for me.sorry to hear about your injury,i know what your going through, but your be back soon.
later