need help making doctors appointment - what do i do?

Hi, first of all, i‘m not a native speaker so please feel free to correct me/ask questions if anything doesn‘t make sense. i also don‘t really know if this is the right sub, so please feel free to redirect me to another one that i should have posted in, if it isn‘t. I just really don‘t know what to do anymore and i‘m really afraid.

I‘ve felt a lump in my breast some months ago (almost a year i think, i‘m not sure though) and i know i should get it checked out, i‘m really scared it‘s cancer (outer upper quadrant, a little painful if you put pressure on it, but not that painful).

The thing is, i‘ve never been to a gynaecologist, so i don‘t really have a doctor i can just go to that knows me already. I have no idea how to find one (for the record, i‘m 17f and live in foster care, so i really don‘t want to talk to my foster parents, i haven‘t been living there for long, i don‘t trust them and really don‘t want to share information that private with them, so i‘ll have to find help myself).

So my question is: do i have to get it checked out or can i just ignore it? If i have to get it checked out, how do i find a doctor and ask for an appointment? (i live in germany and have a paediatrician (similar to a primary care doctor i think, i go to him (he‘s male) for pretty much everything) Can i just ask my paediatrician for an appointment? what do i say to the secretaries while making the appointment?

I really hope this belongs in this sub, i just need help/advice and i‘m really scared, so i‘d be happy if anyone can help. Thank you :)