I found a little lump in my left breast and I'm a guy! It only hurts a little when I press on it. What could this be? – Tyrone* When a guy goes through puberty, all kinds of changes take place in his body. One of these changes can be a condition called gynecomastia, when breast tissue enlarges. That small lump with tenderness beneath the nipple is a normal part of puberty. In fact, about half of all boys develop gynecomastia during puberty. It's usually temporary and can happen on just one side or both. Some guys also may feel tenderness in the breast area when they go through puberty. Breast changes in teenage guys are part of puberty — and they're rarely serious. Some signs that it might be serious are if the lump gets a lot bigger, becomes hard, or if you notice any fluid coming from your nipple. If that happens, see your doctor just to make sure it isn't a sign of another problem — though, again, breast changes in teen guys are almost never serious. Even if you're not worried, it's always a good idea to talk to your doctor about your changing body. Your doctor is your best resource when it comes to your health. Plus, getting used to talking to your doctor now will help you get more out of your medical care as you grow up. *Names have been changed to protect user privacy. Back to Articles Related Articles Gynecomastia Puberty can be confusing, especially when unexpected changes happen. Learn what gynecomastia is and why it happens. Read More Everything You Wanted to Know About Puberty Voice cracking? Clothes don't fit? Puberty can be a confusing time, but learning about it doesn't have to be. Read all about it. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.