Hi there Notaghost1134
Good question! It's good to be familiar with what your own breasts feel like but that's because
changes to how they feel, e.g. new lumps or ones that grow can be a sign of breast cancer. That doesn't mean that all lumps and bumps are bad though! Breasts are made up of all kinds of different types of tissue, and it's really normal for there to be harder bits in there. They can also change over time - e.g. linked to your menstrual cycle - so you might notice them becoming more tender, or more lumpy for a while and then going back. Plus, whilst you're still going through puberty they're going to be growing and changing all the time.
You mentioned squeezing them and feeling something change - if you're squeezing them in a way that hurts then that's probably not a good idea, best to just let them do their thing. Does that answer your question?