Hi, Thanks for the query.
I would like to say that you got a ultrasound
of effected part and there was nothing wrong, that 's good thing.
As age grow in some women there is a dysmenorroea ( pain during period).
You asked that pain is continue even after period is over, that's a worry.
Now note down that this is also related to your's period and due to frustration of pain you develops anxiety
and that is the cause that still you have pain.
So first of all consult a Psychiatrist
and he will advice you proper thing. Thanks. Good luck.