Breast issue

Okay hopefully this isn't too much information... I apoligize if it is!

This weekend quite a large bump showed up on the inside of my breast near where it attaches to my skin. It's very painful, the skin is pink/red and it is hard to the touch. It's not a pimple. Has anyone ever had this? Could it be a blocked milk duct or something like that? I'm 17 weeks pregnant.

I'm not freaking out about it but I will call my doctor tomorrow. Just wondering if anyone has experienced this. Any info is greatly appreciated!