sir, i am a 23 year old male,i used to smoke heavily for past 4 years,which i quit last week because i had a strange feeling at the bottom of my left throat.i also noticed a red painless spot on my mouth roof .i am also having slight lung pain in left lung sometimes i also feel a mild pain in my lower left jaw ,but its so mild that its not exactly to be called a pain,i think i also have a small lump inside my left throat ,is it cancer ,i am scared,please reply as soon as possible.