Jsquared

I smoked in high school and a little bit in college. I am only 28 and I am experiening mild chest pain that comes and goes. It is a pinch pain on the left side of my chest. I have postnasal drip and sometimes in the morning whn I breath in it feels like I've been outside in the smog all day. My doctor has said I most likely have acid reflux and post nasal drip. He performed an EKG and I only had a right bundle block which I was told is common. Other then that everything else was fine. I'm going to a cardioligist to get a echocariogram. He thinks with the pains that I might have Mitral Valve Prolapse. The reason why I posting here is because I want to know if these are symptoms of lung cancer and shouls I be pushing my doctor to be focusing on the lungs?