I have a pain i think in my lung, on my inner chest, usually when i breathe, but not always, it hasn't gone away in a month, could this be cancer?

Unlikely cancer: The pain you describe is most likely pleurisy or costochondritis. Lung cancer is extremely rare in someone your age. There are, however, some other malignancies that present with chest pain in someone your age, (hodgkin's disease, lymphoma, testicular cancer). Try an anti-inflamatory drug, like Motrin or aleve (naproxen). If the pain persists, see your physician for a full physical exam.

Chest wall pain: You mention a both pain on breathing and pain on swallowing and relate the former to your chest wall. Since it's hung on for over two weeks, it would be worth being seen and perhaps an imaging study done though i'd be surprised if it were malignancy.