hard round lump under skin on my left nipple

Katie
I'm 15 and have just discovered a pea sized, hard round lump under the skin of my left nipple. 
It's a little uncomfortable to touch, and my nipple is quite itchy. 
When I try and move it a little, it feels as if it's attached to something, like it doesn't move with my finger. 
My first reaction was to cry.. I know that sounds pathetic but this has been a worry since I started puberty, having cancer. 
I don't know what/if there are any side effects to having first signs of breast cancer, but I have been feeling weak, tired and unmotivated the past few weeks.
My bampi, mum and Auntie have had some sort of cancer. That's what worries me.
Please help me! 

Glow Resources

Let’s Glow

Glow is here for you on your path to pregnancy

Glow helps you navigate your fertility journey with smart tools, personalized insights, and guidance from medical experts who understand what matters most.

25+ million

Users

4.8 stars

200k+ app ratings

20+

Medical advisors