I'm a 14 year old boy and I've had lumps under my nipples for over a year. My friends have lumps too and insist its normal but mine are a lot bigger than all of my friends and its really emberassing
These nipple rocks are known as Gynecomastia in boys. Here is more info for you -
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.