Cancer can cause pain in all areas of the body (muscles, bones, nerves, etc) and not just the areas affected by the cancer itself. One can also develop pain from the treatments themselves (neuropathic pain from chemotherapy that injuries nerves).
Treatment: Medications, nerve pain medications, narcotics or a pain pump. Studies have shown that pain pumps not only lead to a better life for cancer patients, but prolong their lives. It’s much easier than administering around the clock medication, and includes less side effects since the patient receives lower doses of medication (medication going directly to spine where pain is picked up by nervous system). Side effects such as constipation and sleepiness are usually not seen in pumps.