First of all, I'm sorry you are dealing with this. Lymphoma fears are a huge pain in the a$$... it is probably my biggest fear, but it comes and goes.
About a month or so ago, I had a swollen lymph node near my groin for literally no reason. I was not sick, had no injuries or infections. I was pretty much ready to write my will. Then two weeks later, it started to go down a bit. A week after that, it was completely gone. They act up for the slightest reasons, or no reason at all that we can see! DON'T TOUCH IT though! The more you touch it, the longer it will take to go down and it will be a vicious cycle.