My lymph nodes in my neck have been swollen for most of this year. I've had an MRI on them, result: benign. The neck specialist also looked down my throat with a camera (through my nose) and the throat is fine. HIV Test came back negative. All (extensive) blood tests came back within normal params, including liver, kidneys, thyroid, calcium, protein, etc. I even had a brain MRI in case of something like menengitis (came back fine, but with a sinus retention cyst on the maxillary noticed). I do have a couple of infected (supposedly) teeth with cavities, but I don't see how that could cause several months of swollen neck lymph nodes. I've been checked from head to toe, inside and outside with nothing wrong. So what gives with the lymph nodes? They are indeed tender.
Also, in case this helps, I smoke. I had a chest x-ray and the result was unremarkable.