Hi Doctor, Since last 2 months Randomly while sitting i feel that i am not breathing properly,when i exhale immediately i tried to inhale, my spo2 is 97 98 always at that time When i feel breathing problem i try to take a walk for around 40 45 mins ..this happen randomly..due to this i did several diagnosis like ecg,tmt,chest xray 2echo,vitald3 and b12 test..all test ok...in blood test my vitd3 and b12 was low and my bp was 140/90. This breathing irregularities is not going..is it anything related to lungs /heart? No other symptoms or complain..