what are the signs and symptoms of respiratory system?
["Difficulty Breathing. While it's common to feel a shortness of breath during exercise, if it doesn't go away—or is present when you aren't exerting yourself—you should be concerned. ... ", 'Stubborn Cough. ... ', 'Breathing Noisily. ... ', 'Lingering Chest Pain. ... ', 'Chronic Mucus. ... ', 'Coughing Up Blood.']