How can I improve my ROM & reduce skin tightening w/ horizontal abduction/shoulder flexion after gynecomastia surgery? (Photos)

I'm three weeks postop from my gynecomastia surgery and I'm wondering how I can reduce skin tightness and reduced range of motion when I horizontally abduct and flex my arm? I'm not sure if it's scar tissue build up, but when I go to stretch my pectoral muscles or lift my arm above my head there is a pulling sensation between my sternum and medial areola and it reduces my range of motion to about 80% of my normal range