Pain is defined by the International Association for the Study of Pain as an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage. It is the most common reason people seek health care, and because it is inherently subjective, the patient's self-report is the single most reliable indicator of its presence and intensity. Effective pain assessment and management is a core nursing competency that spans every clinical setting, from the post-operative unit to palliative care, and it is heavily represented on the NCLEX-RN. Nurses classify pain to guide treatment. Nociceptive pain arises from actual tissue damage and divides into somatic pain (skin, muscle, bone), which is well localized and aching or sharp, as in fractures and surgical wounds, and visceral pain (internal organs), which is poorly localized, cramping, and often referred, as in bowel obstruction or myocardial infarction. Neuropathic pain results from nerve injury or dysfunction and is described as burning, shooting, electric, or tingling, as in diabetic neuropathy, post-herpetic neuralgia, and phantom limb pain. Pain is also categorized by duration: acute...