Ri?

I'm starting to wonder if my boy has an RI. I'm probably being paranoid, but I AM a smoker (not in the house), but I do also smoke for ya know...medical reasons :P He's not in the same room as I smoke, but now it worrying me. All his temps/humidity are correct, isn't making any sound breathing, and is acting totally normal except maybe a little more active?
But he has started resting with his head elevated on his hide/log whatever is near by. Doesn't do it ALL the time, but it's definitely getting more prevalent. He also is breathing a lot...deeper? He "expands" more when taking a breath now.
Is this normal or should I be worried?