Dear friend, welcome and thanks for entrusting your query here at HCM !
Fast heart rate
is a normal response after strenous activity.
If you feel unusually breathless too, it could be of respiratory origin.
One sputum negativitiy does not rule out TB. you need at least 3 consecutive sputum samples to be tested.
Xray finding can have many differentials.
Please discuss differentials and further testing with your doctor.
If possible, could post your Xray image here so that I can comment better?
Please describe each symptom in great detail.
I hope you are fully satisfied with the guidance I gave.
I would be glad to answer any further queries.
Thank you and Good luck !