The opening cervix actually goes back during arousal, which gives length and some width to the back of the vagina. At most the whole length is going to be somewhere between 10-15cm average with some give at the entrance of the cervix still, until it gets a bit hurty.
The penis cannot hurt the ovaries because it can't get through the cervical wall, let alone up into the cervix, through 3cm thick muscle at a 90 degree angle to the ovaries.... That would be some feat if it could and it wouldn't be a nice experience for either party LOL
If a lady is complaining of pain the next day or during, then you've either leaned on her soft pelvic region during sex (which is damaging to the ladies to a certain extent, so don't do it) or it's just because you've pounded her cervix opening and it's bruised. And that HURTS so don't do it!
Hope this info helps?