Been about 8 months i been feeling different been feeling something covering my heart beat / pulse slowly. feel weak no energy like running out. i workout or try to run i don't feel my heart working hard tests normal except pft showed airway disea. ?

Airway disease: Have a lung disease (airway disease) such as asthma or bronchiectasis worsens your lung function and decreases the ability of your lungs to supply your muscles with oxygen. Airway disease makes you feel weak and like you do not have enough energy to run. You should talk to your doctor about treating your airway disease (for example, with an albuterol inhaler) to reduce your symptoms.

What tests? : That were normal? There are many tests that are needed given your history, after a good history and physical examination, you already mentioned abnormal lung functions test, could an obstructive airway disease such as asthma, but still other tests to rule out heart problems need to be performed,, at least an ECG and may be a cardiac stress test, kindly revisit your doctor or get a second opinion,