Bad cough for about 2 and a half weeks, sometimes thick green phlegm, pain in lungs breath in deeply. what could this be?

See below: Acute viral bronchitis can give a productive cough with yellow/green sputum lasting several weeks. Pain on deep breath may be due to chest wall strain from coughing. However it can be a sign of pneumonia, particularly if you have fever or shortness of breath. You would have to see a physician for proper diagnosis and treatment if concerned.