Mike,
From one canuck to another, welcome eh!
The biopsy you had should give a conclusive answer to the cause of the swollen node. I have to say...Stop Smoking Already!! regardless of the results. It just doesn't do anything to help you out. (Ok, I'm off the soap box now...sorry...you know better though!)
Many things can cause inflammed and/or swollen lymph nodes. Infection, inflammation, trauma, family history, chronic diseases like arthritis etc., autoimmune disorders, and yes cancer.
You say it has been there a few years, how many is a few? Is there any history of cancer in your family?
Do you have any other symptoms (pain, tenderness, improper muscle function, trouble swallowing etc.)?
You are absolutly correct when you say you can't dwell on the past but, you can start right now to help influence your future.
You made the first step by having the biopsy.
I hope and pray that everything is OK for you.
If I can be of any assistance please contact me.
All the best.
Mike