Hi, I am a 16 year old guy from Spain (yeah from Spain, idk about any fitness spanish forum so..) and I've been lifting for like 7 months. I've noticed many changes, many, I've seen a lot of videos and images but I've never seen this and I don't really know what it is.



I don't think I have it on my left side

Sorry for my english and thanks guys, I'd appreciate any reply