Could this be lung cancer?

Im 16 don't smoke and im a huge hypocondriac and I go through episodes like this every week. But this week ive been having very small chest pains and tingling in my throat. When I cough up phlegm there is a tiny bit of brown in it but when I blow my nose its still green. I know this probably nothing. Like it could be cause I have been eating alot of chacolate ive cream or ive recently started taking prozac but I just want to be sure