lung cancer is adolescence is very rare. There are a few things that could be causing the pain and coughing. Tuberculosis comes to mind. Nothing to serious but if you have come into contact with someone that has it TB can be very contagious. Also more common in young men are pnuemothorax. These are common in young men because the ribcage grows faster than the lung. This can cause shortness of breath pain and coughing. A simple pneumonia can also cause the same symptoms. I wouldn't get to concerned until you get a chest x-ray. I'm not saying that you have any of these conditions I'm just giving you examples of other things that can give the symptoms that you describe.