My left lung hurts I just cut down on smoking yesterday and body aches?

Lung or chest pain. Pain in the lung could be from a blood clot, inflammation in the lining or inflammation of an infection. Smoking make all of these more likely. Please get this checked by you doctor, and if the pain is severe or you are short of breath, go to the emergency room.
Follow up. See your health care provider for an updated exam, and possible chest x-ray .