How painful are they?

If you ask 100 menstruating women, you will get 100 different answers.
For some, there is no pain. For many/most, there are degrees of discomfort, aches, some cramping (a feeling that something is squeezing her insides over and over), and an overall feeling of not being well. For some, there is intense pain that makes her unable to function at all.

I used to describe my years aged 12 - 50 as feeling like someone stuffed my abdomen with a hot heavy weight during menstruation. The days leading up to it were no fun either.