For cancer patients, acute pain can be the result of surgery, a broken bone or some type of obstruction. Sometimes, the pain is a side effect of treatment, such as a sore mouth from chemotherapy, post surgical pain or skin irritation after radiation. Chronic pain, on the other hand, may or may not be as intense, but it's usually just there in the background. The level rises and falls, but it never seems to go away. It just keeps nagging and throbbing.
Many factors can contribute to chronic pain.
Most pain experts now believe that almost all unexplained chronic pain is rooted in a physical problem, such as damaged or inflamed nerves, blood vessels, and other tissues, or other sources which can't be easily explained. Such pain may also simply be the cumulative effects of a prolonged illness. Unfortunately, chronic pain often leads to inactivity, causing the muscles to become weakened. The weaker you become, the more difficult it is to take part in exercises that could strengthen the muscles. Chronic pain also interferes with sleep, leaving you depressed and lowering your pain threshold.