Sir, i am confuse that i have chest fat or gynecomastia ,because when my body pumps up by doing running ,exercise and even i bath with cold water then my chest nipples becomes tight and come outside of that black area ,but when my body relaxes then my chest nipple muscles loses and nipples goes inside that black ring and my chest look like weird and whole chest loses and doesn't look good at all,please tell me what it is a chest fat or gynecomastia.