Welcome to HCM.
There could be many causes for this. It could be a sequel of your child hood asthma. The childhood asthma
may not be asthma but bronchitis
or other lung infection
You need a detailed examination by a chest physician, as well as chest x-ray, blood tests etc. to find out the cause of this problem. You may even need an ECG to exclude cardiac problems.
You should not ignore these symptoms and must consult a good chest physician immediately.
Wish you speedy recovery.