Thanks for your question on Healthcare Magic. I can understand your concern. Since your extensive work up with x rays, CT scans and blood reports is normal, no need to worry for major heart or lung related diseases. Uncontrolled stress, anxiety and panic disorder can cause similar kind of symptoms. So better to consult psychiatrist and get done counselling sessions. Try to identify stressor in your life and start working on it s solution. Along with anxiolytic drugs (Xanax and Celexa), counselling plays very important role in management of stress and anxiety. So don t worry, you will be alright. Avoid stress and tension, be relax and calm. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.