Uitklapstoel

I have a lump uner my left nipple aswell. I've been told that when it's a tumor it shouln't hurt, and mine does (when touch/pinching it).

More people told me its normal, but im still concerned. should I get it checked out?

Thats what I heard aswell, Im 19 years old and just started working out 3 months ago, i've been told that can be related aswell. But I'm gonna let a doctor watch, you can never be sure enough.