For a few months i have had an oval lump on my left shoulder and when i move, the bump moves with the muscle. so i figured i tore a muscle and its just healing. but tonight I finally wanted to see what was in there so i got a 23g syringe and aspirated. yellow puss came out and i got scared so i only collected 1/4cc. there is still plenty left and i am very worried. does anybody know what it is??