Asthma is a chronic disease that includes broncho-constriction (tightening of the muscles around the airways) and inflammation (swelling) of the bronchial tubes. During normal breathing, air flows freely in and out of the lungs. But, during an asthma episode, the lining of the airways swell, muscles around the airways tighten and mucus clogs the tiny airways in the lungs, making breathing difficult. The airways become overly responsive to environmental changes, sometimes resulting in wheezing, coughing, breathlessness, or tightness in the chest....................