I Found A Small Lump On The Back Of My

I found a small lump on the back of my neck it dosent hurt but I know that it is there. I was around alot of dust and mildew three weeks ago and also ended up with alot of sinus drainage from it and sneezing. I noticed the small lump two weeks ago it dosent hurt and hasnt got any bigger do you think I should worry about it or should I go see a doctor about this all my other symptoms seem to have stopped.