24/m. difficultybreathing. sinus series chest xray all negative. no help from standard rx's; only relief came from magnesium iv. dr out of ideas, help?

Rule outs...: You will want to make sure you don't have asthma, which might not show up on xray. A clear chest xray rules out pneumonia, while a negative sinus series makes acute sinusitis unlikely. Is your trouble breathing in your nose, your throat, or your chest?

More detail needed: Difficulty breathing can be from a number of different problems to include anatomic, environmental, as well as perceived. Are you having difficulty in your nasal passages, or in your throat or chest? Is it just as difficult through your nose as your mouth? Anything from allergies to air contaminants to seasonal flora to cardiac or true pulmonary or even reflux like issues could contribute.