I have been dealing with the same thing on and off for over a year now............last summer, I was put on meds for sinusitis, after I came off the meds I have had all sorts of crazy things happen that I have never had before and now my breathing issues are so much worse! I have never had asthma or breathing issues before in my life.........I have been to the ER several times in the last year for breathing problems and they have taken x-rays and say I'm fine.........I have been to the cardiologist for a nuclear stress test and a monitor, my heart is fine..........they have tested me for asthma and say I don't have it...........so, I deal with these come and go breathing issues, just like you mentioned, and no one knows why...........they have said anxiety (which I don't have) and depression (which I don't think so). The only thing depressing me is not being able to do normal things anymore, like clean the house and things easy like that, without trying to get a good breath.......I have noticed if it is hot outside or the humidity is high, it is a lot worse...........if you find out anything, please share..........I will share if I find out anything either..........I go to the dr.'s in dec., when my insurance starts............:-) Also, I saw an allergist and they tested me and he said I have allergies to dust mites, so I have had the carpets cleaned, bedding covered, pillows covered, etc. I do not understand this and I am only 35.........:-( The allergist also said he thinks I have silent reflux effecting my sinus' and I am wondering if it is effecting my lungs as well........anyway, thanks again for any advice.
You should ask the pulmonologist, whose diagnosis was "a severe respiratory infection", where the infection resides. Is it pneumonia, a lung abscess, and why might it last 6 weeks? If it is severe, why is there no fever and not much phlegm. If your lungs truly are clear and your chest x-ray shows no significant abnormality, the shortness of breath is worrisome. If you haven't had an x-ray recently, you should have another one taken. You could be having clots to the lungs, called pulmonary emboli, and your x-ray could be clear. Your doctors should also assess your heart, as it could be responsible for, otherwise unexplained, shortness of breath. Young people seldom have heart attacks, but not infrequently, have a cardio-myopathy.
Good luck