Found a breast lump...now what?

I know this isn’t period related, but I’m really worried and I felt like I was most likely to get a response here since there are so many members. Basically, I found a lump in my breast a couple months ago. I have hypochondriac tendencies, so I tried to avoid running to the doctor immediately. Since then, the lump has gotten slightly bigger and the area is always tender, not painful, just slightly tender. More recently I notice a smaller, more firm lump near the same area. I also noticed that the breast with the lumps doesn’t quite fit in my bra like it used to.

I’m planning to go to the doctor, but I don’t know who to go to. I’m 20 turning 21 in a couple months, so I still have my pediatrician until I turn 21. I don’t know if I should go to her, a different doctor, an obgyn, or if there’s a doctor specifically for this issue.

Sorry this is so long, but please help😓