What Causes Fatigue And Shortness Of Breath In A BOOP Patient?

I have a history of BOOP Or COP. I have been off prednisone for about 2 months but I am still on imuran. I have been feeling fatigued and short of breath for about 2 weeks but a chest X-ray is clean. If a relapse the X-ray should show nodules. What test should I ask my Dr to perform? What else would cause these symptoms? This is the first time I have had these symptoms and it wasn't the BOOP returning.