You need Pulmonary Function Test to R/O any copd and or pulmonary restriction. Make sure they order a DLCO (diffusion capacity (oxygen transfer)) on the test. Do you have a smoking history? Have you had a xray and an ECHO? Talk to your doctor about your dyspnea (shortnes of breath).
Good luck.
Yes, i would agree that you must go at least one step further. The next step that you have to make is to STOP SMOKING NOW !!!!
You may think that that is too hard to do but look at what you are going through now. Be kind to your self and spend some time in meditation. Listen to the indwelling presence of spirit and know that you will find the answers that you need to find.