How do you know what position baby is in

I’m 32 weeks and I’m so much pain all the time because of however my child is sitting in me. I don’t feel many kicks, just a punch of twisting and that’s usually on the side of my belly and up top right under my boobs. However last night I felt a ton of movement near my vagina , like where the pubic hair grows, it felt like kicks.

I’m on baby number 3 and wonder this each time lol.

Also when do they start measuring your belly and how does the dr check what position baby is in?

I can’t for the life of me remember frozen my previous pregnancies.