I am hearing noises in our attic. I can hear it running back and forth and its claws on the ceiling.?

Is there something we can do ourselves, or do we need to call an exterminator. It is more apparent at night. How can anything stand the heat up there? We think it could be a mouse....although I heard more than one, or squirrell. Also we have experienced an odor in our house, possibly coming from our varmit?