Birth control meds are commonly known to have side effects of both headaches, and swollen lymph nodes
. On top of that, most antibiotics very commonly cause
4. Despite it being somewhat hard, if this node is even slightly moveable, this would almost guarantee it to not be any form of cancer. And on top of that, you lack any of the typical symptoms of cancer.
5. The fact that the node fluctuates in size at all would also indicate that this is not a cancer.