I have had a chronic what I term a blockage in my upper respiratory area for some time now. It's like I cough but can't bring it up. I have lots of mucus in the mornings (clear) that I bring up but after the day goes along, that upper respiratory thing is always there. I get reflux/heartburn a lot. I went to my primary about a year ago and he sent me to cardio for an echo, stress test etc... He checked my thyroid gland with no definitive Dx or problem. I get SOB easily with activity (I shouldn't, I've been an athlete my whole life) and I get light headed to the point of fainting with min-mod aerobic activity. It forces me to lie down. Echo was (-), stress test too. Cardio guy said I have vagal nerve hypersensitivity and that dehydration can make it worse. Any ideas?