Imagine you a woman who is on her period time. Her menstruation has always been very painful. Which one of the following sentences would be idiomatically acceptable to indicate that the woman is having pain right now:
I’ve got cramps because I’m having my period.
I’ve got abdomen ache because I’m having my period.
I have pain in my abdomen because I’m having my period.
I don't know if the mens. pain has something to do with abdomen in English logic at all or not, but it would be possible for us to say such a thing in our language.