Hi, there's nothing there that makes me think of lymphoma.
It does seem instead as if it is from spreading inflammation. There could be some infection present. Sometimes there is an 'occult' (which means 'hidden') infection that is the source, but might not be known for now.
If it gets into the throat area, bacteria or a virus can travel downward to the lungs.
Much less common, there can sometimes be inflammation without any infection.
The pain is probably from the swelling. Btw, lymphoma is not usually painful.