Dear friend, nothing in this world could be learned without an instructor. any kind of exercise regimen has some prerequisites and their compliance is must to implement them. Yoga
is also a kind of Physical workout and it deeply involves your system, therefore an analysis is always required before starting yoga. Many people have harmed themselves by following such practices. My suggestions for you are:
1. half Knowledege is always dangerous so stop following practices, it is because of this people spend their vital years in getting an expertise.
2. Consult your General Physician, he will be the right man to analyse your case, you may have to get done a few investigations like Chest X-ray, CBC, etc. you said that you are hoarse and short of breath so that suggests it may be an infection of Lower Respiratory Tract
. Start Gargles and steam inhalation, that might help you.