Asthma is a type of respiratory disease in whcih the lung's air passages become too narrow and has excessive mucus production. This will lead a person to experience difficulty of breathing, coughing, and tightness in the chest area. Asthma attacks occur when it is triggered by allergens, strenuous activities, and stress.
We can suspect that Melissa probably has asthma based on the symptoms of coughing for several days and she is experiencing difficulty in breathing.