Asthma is a chronic disease that affects the respiratory system. During an asthma attack, bronchial tubes, which carry oxygen from the lungs, tend to tighten and thereby reduce the flow of air into the lungs. Airways become inflamed and also covered with mucus. Symptoms may occur several times a day or a week or less. Severity of attacks also changes. Several factors may be responsible for causing asthma attacks and shortness of breath along with it. Asthma can also cause chest pain and unconsciousness.