I have a small knot on side of neck right kinda under end of jaw bone close to ear and I'm scared it's cancer?

Get it checked. Knots & lumps can be in the skin or under the skin. Knots that are hard, painless, seem to be stuck to something underneath or in the skin and have ill defined edges are usually bad. Those that are soft, tender, move easily and have a distinct edge are usually not bad. Your lump could be a enlarged lymph node or a sebaceous cyst-or it could be something worse. Get it checked by your doctor.
Seek dr care. It is hard to tell if it is anything or not. It might just be a simple small lymph node but nobody can tell you anything without an exam. Seek medical attention especially if it has been there for a while and it is not going away.