I have a palpable supraclavicular lymph node that has been there for a long time around 6 months or more is this a cancer?

Not necessarily: Go to see your doctor and have your doctor examine it. If it is significant, further evaluations may be warranted. Lymph node enlargement can be found anywhere and can be due to different things like infection, inflammation, autoimmune problems, trauma, neoplasm/cancer etc.

Supraclavicular node: Well a normal person does not have a sc node that you can feel. If that is what you are truely feeling it shouldn't be there. Now it could be from an infection...Check your hand and arm over real good for cuts and scratches(do you have cats?). But than you really should get it checked out. Lung and breast cancer can easily spread to this area as can cancers of the mouth and throat.