I have a fairly hard lump on the back of my left arm a little above my elbow. I noticed it a year or more ago when it was about the size of a pea. It's now giving me some pain in that area any time I lift.(I'm a child care provider so I do quite a bit of lifting.) It's about the size of a large marble now. Should I have it checked out? I always just assummed it was a lymph node or something but now I'm concerned it may be something more. Thanks, Sue