Thanks Merry and Sue for your responses.
I never heard of "exercise-induced bronchoconstriction" and no, my doctors (family, pulmonary, and cardiology doctors) haven't mentioned it but after reading Merrie's linkage to the Mayo Clinic's website I think it's a possibility since my issues matched most of the listed symptoms :
* Coughing (no) • Wheezing (no) • Noisy breathing (yes) • Shortness of breath (yes) • Chest tightness or pain (yes) • Fatigue during exercise (yes) • Poorer than expected athletic performance (yes).
I'll suggest my doctors to look into this possible cause the next time I see them.
BTW, as Sue has said "I always got it from exertion in high heat/humidity", my problem seems worse when I play tennis around noon time or during high heat. However, I had been playing tennis for 40 years, and did lots of swimming, running, cycling and never had this problem until 10 days after the second Covid vaccine shot. So I tend to agree with Merry : 'even though the vaccine does make us very sick, our immune reactions can go "behind our backs". Perhaps your immune system put some strain on your lungs'. Yes, my immune system could have over-reacted since I was sick for 4 days after the second shot. I had headache, high fever, high blood pressure, rapid heart rate, fatigue (something rarely happens to people in 65+ age group * I'm 65 year old).
My doctors will look into my lung system again by performing a "pulmonary function test" next, then my cardiology doctor will look into the heart by doing a "calcium score test" and a "echocardiogram".
Thanks so much for your insights. I'll let you know the progress.
Kevin Tran