How to tell if coughing up light green mucus warrants antibiotic along with tightness in chest and using inhaler at night. No fever, clear nasal mucus?

See below. Coughing up green or yellow mucus is most often due to a viral upper respiratory illness (common cold) with bronchitis (which is almost always viral). This won't respond to antibiotics. Coughing up green/yellow mucus can also be a sign of pneumonia, in which case the patient often has a high fever, possible chest pain on breathing and shortness of breath, and feels quite ill. Pneumonia requires Rx.