Unfortunately it sounds like she's losing interest in the relationship in general because you are getting vague nonsense answers about 'it's her ex, no it's not', 'it's painful, but she's not sure', etc.

She's about to breakup with you. If she were 'in pain' she would run to the doctor. It's bs to not have sex and withdraw from the relationship and the mention of the ex is a huge clue that that is the reason.
Originally Posted by boulderboi2017
It's physically painful for her, she hasn't said what's causing. I don't think she's hung up on her ex