Feel a lump on the right side of my neck?

Caught a virus from my boyfrien(at least I think it is a virus because that is what the doctor said he had). Started with a cough. Coughing up brown phlegm, now my nose stuffed up, can't sleep well because the congestions in my chest makes too much noise and feel like I can't get enough air in. Had a fever of 100 for about a day and a half but that broke yesterday and hasn't come back. Anyways today I was just rubbing my neck and on the right lower side of it felt a small lump. Doesn't hurt and can't see it....I don't have a sore throat. Should I be concerned that this can by lymphoma or am I overreacting?