I have a swollen lymph node on the inside of my left arm just above my elbow.

It has been there for quite a while (maybe a year) and hasn't changed shape or size. It is slightly tender to the touch but I wouldn't even have known it was there if I hadn't happened upon it one day. The last few days I've been having some numbness in my fingers that comes and goes on that same side. I have also had some joint pain. I know swollen lymph nodes are supposed to be one of those things that are a sign of something bigger and I was wondering if you had any idea what it might be. I have a doctors appointment this week but I'm really worried that it might be cancer or something else serious. As far as family history goes I am 23 and no one that I know of in my family has a history of cancer of any kind.
Thanks.