Is my one year old cat trying to tell me something?

My one year old, Raja, and I have been living with my boyfriend for the past two months. We'll be staying there until my new apartment opens up on July. When Raja was a baby, she used to pee on my couch until I was able to train her not to do so. I was worried that she would begin to pee outside the litterbox in my boyfriend's place, since it was a new environment. But she was perfectly fine once we got there. She is more than acclimated with his place AND his dog, and has been for almost a year. But recently, she's been peeing on the spare bedroom mattress at night. Is this an attitude problem? Is she trying to tell me she doesn't like staying there? Also, I can't seem to find a pet odor spray that completely takes out the smell. What should I do?