Pulled Pectoral muscle

HiI recently pulled (at least I think it’s a pull) the muscle that attches from my right breast to my shoulder along my collar bone. Can you picture that? 🙂 Anyway, I did this while training in martial arts and it was while throwing several hundred punches. Feels worse in the morning for some reason and if I stretch. Can you recommend any excercise or stretching type movements to help speed healing and releive the discomfort? Is ice good for this or should I apply heat? Thanks.