Whats this lump in my ?x?

Hi i am 16 and yesterday i was exploring my and right at the back of my and up abit there is a lump, which feels to have a hole in, I am wondering weather it is my cervix or somethink more sinister, The doctors told me last time because of my symptoms i could have a ovarian cyst and this was before i even felt the lump, i am worried because i dont wanna say to my mum how i found this lump. as she will no i was exploring my body. How can i come across to tell the doctor with out feeling ashamed ?xx