Hello. I Have A Bad Habit Of "self Diagnosing".... I

hello. I have a bad habit of "self diagnosing".... I have had a heartburn problem for some time. I will get (sometimes-not all the time) a quick chest pain in the middle of my chest. I have lots of phlem latetly. I do smoke---less than a pack a day. today, I put my head back & felt my neck.... on the right side (where the bottom of the neck meets the chest, there was some swelling. I always think the worst. no fever, no weight loss, no discoloration, I am over weight. no rashes....or anything.