Swollen lymph nodw under jaw on either side of the bones of the throat.?

The lymph nodes under my jaw have been swollen for over a month, but they returned to normal size after I stopped messing with them every day. However, I noticed that the one on the right can be hard at times. Sometimes it's soft and squishy, but the more I mess with it the harder it will feel. I don't have any other hard or swollen nodes, nor do I have any other symptoms of lymphoma; still I find myself concerned as I'm eighteen, right within the age range. I feel quite healthy, and have, in fact been more active than usual. I'm aware that no one can diagnose me over the internet, but I can't particularly afford a trip to a credibile doctor at the moment and I'm looking for some reassurance on the whole matter. I should also probably state that the node is entirely mobile and not fixed in one place. I have seasonal allergies, ie. a slight cold that will come and go, but no severe flare ups other than the occasional build up of phlegm in my throat. Could this have any affect on my lymph node, and if so why is it localized to only one side of my jaw? In ant case I'll be entirely grateful to anyone who can offer some assistance.