Final answer:
Inflammation of the air passages in the lungs causes increased mucus production, wheezing, and difficulty breathing.
Step-by-step explanation:
Asthma is a chronic inflammatory disease of the airways in the lungs, in which the airways periodically become inflamed. This causes swelling and narrowing of the airways, often with excessive mucus production, leading to difficulty breathing and other symptoms.
Common symptoms of asthma include wheezing and difficulty breathing. Wheezing is a high-pitched whistling sound caused by the narrowing of the air passages in the lungs. Increased mucus production is a result of the inflammation and can contribute to the feeling of chest tightness.