Cancer is an abnormal growth of cells that create a tumor. Cancer can be very painful. Sometimes the tumor presses on bones, nerves, and other organs. Some cancers, like pancreatic cancer, have no symptoms until the tumor is large enough to press on nerves and cause pain. This is called referred pain. For instance, liver cancer often includes right shoulder pain.
If you have chronic unexplained pain, weight loss, and fever, you may want to consult a doctor.