What Type Of Test Do I Need To Determine If

what type of test do I need to determine if I have beginning stages of lung cancer? I don't have breathing problems, haven't smoked since 1976 but was light smoker before 1976. I am 71 yrs old. I had a chest xray 2 yrs ago, but it was negative. ENT dr. said I had allergies and sinus problems. have cough w/congestion in throat, constant throat clearing all day. feel very tired and take nap each day 2-4 hrs. weigh 122 lbs, eat lots veggies, fruits, lean chicken or fish, no red meat or bacon, sausage in over 10 yrs. where can I find pulmonary specialist in Columbia, SC??