APII: pain treatment

With pain, there are structural, functional, and psychophysiologic factors involved, and so it is difficult to measure since it varies from person to person. Some forms of pain don't respond well to painkillers, so often times there isn't much you can do. Therefore, chronic pain is difficult to treat because of limitations in pharmacological options and because of dose-limiting side effects in available treatments. On the same note, there really isn't no agreed location to which to target therapy to treat pain. For example, pain from one area of the body, such as in cardiac ischemia, can be felt in another area, such as the neck and left shoulder - a phenomenon called referred pain.