Hello All I have exact same symptoms as Posted by gabrielm @gabrielm, May 31, 2018 . I had it in 2017 after fe weeks effort it went away , i also had very irregular beats & palpitation in 2017 & 18 . was on beta blocker for some tine and took anxiety meds too. Recently did heart echo and chest CT scan all came normal blood work normal . im not over weight , doctor says anxiety but that feeling of not being 100% is really frustrating , Like gabriel i try to work out 3 to 4 days a week . Take ..25 mg xanax for sleep because sometimes i wake up gasping for air . I know i have an over active brain which overthinks . so i believe these symptoms could be over heating of brain . resting helps but then mind wanders back and symptoms start again . Im taking take prone 30mg daily with vitamin D 50K on weekly basis . I live in UAE and we dont get enough sunlight here so 90% of the population is vitamin D deprived . Even though i have done numerous heart and lung tests which came normal it feels like that my SOB is connected to them . One strange thing happened that palpitations complete stopped and this SOB thing started . ( Just for reader s to know that i was smoker for 10 years quit in 2010 again started light smoking (2-3 Cigarettes in 2018 and now off smoking again ) . I had some traumatic events in life which sometimes pop up in mind but i wonder what exactly is this disease which medical science rules out as anxiety but i get strong physical symptoms . Sorry for my random mentioning of events but im sure somewhere somebody could relate and give an answer -