Since many years ago (about 15) I have noticed palpable lymph nodes on the posterior triangle, on both sides of my neck, one week ago I felt a little pain (it only lasted for some hours) on the right side of my neck, and noticed it was swollen, it's clearly visible specially if I turn my neck towards the opposite direction, about 2 cm in diameter, it feels rubbery, no redness on skin, no pain at all, I don't feel like it moves at all, maybe bend a little but no displacement while touching it. About 4 days later I noticed a small lump, maybe less than a cm, in what I believe is called the "upper jugular" area, I think it corresponds to level 2 lymph nodes, it feels hard, unmovable and clearly visible if I look upwards (towards ceiling).
What could be the cause?
I'm 30 years old, have smoked a pack a day for about 15 years, social drinker.
Don't know if relevant but about a year ago I started losing weight (unintentionally), followed after by lack of appetite. I also sleep 12 hours a day. But this last symptoms could be due to depression (not sure if I have that, but I do show a lot of signs)
Thank you for your time.