Upper respiratory/ Chest soreness/ Pressure... Buckle up, this is a LONG one...?

It very well could be stress. Stress masks itself in many ways and can make you sick. With that said I suggest you do what your doctor has requested you to do. Get the CT Scan. It doesn't take that long and it will rule out a pulmonary embolism or any other problems. Talk to your doctor about the stress you are under and see if they can prescribe you something to help you deal with it better.