Given that you are having no trouble with your breathing and that your chest x-ray and physical exam of your lungs is normal, the likelihood of your having lung disease as the cause of your “hallow like breathing feeling” is extremely low. Such a symptom is usually a reflection of anxiety and it is possible that the anxiety may have either originated or been heightened by anxiety over your heart, “not beating right”. You may be having an abnormal heart rhythm and this could be the case, despite a normal EKG and stress test. Your doctors may want to consider ambulatory heart rhythm monitoring, the duration of the monitoring to be set on the basis of the frequency of your heart “not beating right”.
The development of increased mucus cannot be attributed to anxiety, although the reverse could be true. In this regard, the normal/negative CT scan of your throat is very reassuring. Increased mucus can originate anywhere in the respiratory system, lower or upper, and the upper would include your nose, sinuses and larynx. Your doctors might want to consider direct fiberoptic exam of these areas and CT scanning of any of them not included in the “throat CT scan with contrast.”
Note; they did find 3 nodules on my lung in the cat scan that they need monitor the largest was 5mm'