What is a knot that has come up on the top of your shoulder bone?

A knot that has come up on the top of your shoulder bone is likely a ganglion cyst. Ganglion cysts are fluid-filled sacs that form on the tendons or joints of the wrist, hand, or foot. They are usually benign and not cancerous. Ganglion cysts can be caused by repetitive motion, trauma, or an underlying medical condition. Symptoms of a ganglion cyst include a lump, pain, or weakness in the affected area. Treatment options include observation, aspiration, and surgery.