What does the pain feel like when giving birth?

ok so im in my 3rd trimester and ive started to think about the birth, its my first, and i was talking to my mum about it and she said it feel like a car parks on your pelvis, wich has freaked me out a bit, is it really this bad? i wanted a natural birth because i just feel its better for the baby and i really dont like needles. my mum said i'll change my mind. i just wanted to know how painfull it is? because i want to be ready lol.