If this has been chronic enough for two years, I honestly do think you should be worried. But, cancer is not what I am thinking it is. It could be cancer, but it does sound like you might of have Mumps, which does cause saliva glands, the uvula, and sometimes spreads to the lymph nodes and swells up. It could damage left from Mumps, or it may be a problem within your immune system. The immune system is not perfect, and does mistakenly attack our own cells for pathogens. I think you may need a blood test to determine what antibodies in your bloodstream are directed to. If this is not because of autoimmune lymphonitis (also called lymphitis, or lymphonitis) then it most likely could be cancer. But, you must know, lymph nodes tend to swell if it is trying to fight an infection, but I don't think you would fight an infection for 2 years.
It sounds like a reactive node, which leads me to believe it's reacting to an infection and not something more serious. Sometimes lymph nodes swell when you're fighting an infection, cold, etc. and the nodes don't always go back down to their original size. This would explain why you feel the lump even when you aren't sick and it gets bigger when you are. Still, I think it's a good idea to have it checked out by your doctor.