I have a tiny moveable nodule below my collarbone towards my shoulder, what is it?

[Ruby090717]

I have a moveable little nodule below my left clavicle close to my shoulder. I didn’t notice it until I went to the chiropractor for pain in my left shoulder and he found that my tendon is closer to the midline of my body and while he was feeling around he found a nodule just under my clavicle. He hasn’t seen this before in any of his patients and he was quite confused and suggested I get checked out by a GP (already have an appointment but it’s not for a while). He also noticed my lymph nodes have been swollen and I’ve known they have been for quite a while but I have no unusual symptoms of any kind such as runny nose or cough or anything. I’m worried it could be cancerous? I also hardly ever have an appetite and I can never eat a full meal in one sitting, however I’ve been like this for a year or two.