Cause - GENERALLY in all respiratory diseases Food pattern is the cause.
Next cause is defective excretion(motion, sweat and urination in the order)
Finally emotional state. See which is defective and correct it. proper way
To correct food pattern - Change eating and exercise habits, (early exercise followed by bath and reasonably heavy breakfast), early and easily digestible dinner followed by drinking of hot water reduces distress of respiratory tract considerably.
In food article reduce irritant, fermented, spicy, stale, packed food.
Do not control natural urges beyond certain limit
If you have other diseases check for their causes and change them.
In Ayurveda control of emotional state is advised.