Shortness of breath after a cold may be a sign of infection spreading from the upper respiratory tract to the lower respiratory tract and worsening, mostly due to wheezing bronchitis or bronchopneumonia. Shortness of breath refers to increased respiration, so it is important to go to the hospital and have blood tests, chest X-ray and other related tests. Especially for infants under 6 months of age to wheeze mainly, capillary bronchitis is more common, cough is not the main signs, the disease develops faster, because of the age of young and even prone to heart failure, etc., and serious cases can be complicated by encephalitis, so we must consult a doctor in time to avoid serious consequences.