Pain Measurement: Scales, questionnaires, tests, and other methods used to assess pain severity and duration in patients or experimental animals to aid in diagnosis, therapy, and physiological studies.Pain: An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.Chronic Pain: Aching sensation that persists for more than a few months. It may or may not be associated with trauma or disease, and may persist after the initial injury has healed. Its localization, character, and timing are more vague than with acute pain.Pain Management: A form of therapy that employs a coordinated and interdisciplinary approach for easing the suffering and improving the quality of life of those experiencing pain.Pain Threshold: Amount of stimulation required before the sensation of pain is experienced.Pain, Postoperative: Pain during the period after surgery.Low Back Pain: Acute or chronic pain in the lumbar or sacral regions, which may be associated with musculo-ligamentous SPRAINS AND STRAINS; INTERVERTEBRAL DISK DISPLACEMENT; and other conditions.Back Pain: Acute or chronic pain located in the posterior regions of the THORAX; LUMBOSACRAL REGION; or the adjacent regions.Neck Pain: Discomfort or more intense forms of pain that are localized to the cervical region. This term generally refers to pain in the posterior or lateral regions of the neck.Abdominal Pain: Sensation of discomfort, distress, or agony in the abdominal region.Pain, Intractable: Persistent pain that is refractory to some or all forms of treatment.Pelvic Pain: Pain in the pelvic region of genital and non-genital origin and of organic or psychogenic etiology. Frequent causes of pain are distension or contraction of hollow viscera, rapid stretching of the capsule of a solid organ, chemical irritation, tissue ischemia, and neuritis secondary to inflammatory, neoplastic, or fibrotic processes in adjacent organs. (Kase, Weingold & Gershenson: Principles and Practice of Clinical Gynecology, 2d ed, pp479-508)Pain Perception: The process by which PAIN is recognized and interpreted by the brain.Facial Pain: Pain in the facial region including orofacial pain and craniofacial pain. Associated conditions include local inflammatory and neoplastic disorders and neuralgic syndromes involving the trigeminal, facial, and glossopharyngeal nerves. Conditions which feature recurrent or persistent facial pain as the primary manifestation of disease are referred to as FACIAL PAIN SYNDROMES.Acute Pain: Intensely discomforting, distressful, or agonizing sensation associated with trauma or disease, with well-defined location, character, and timing.Pain, Referred: A type of pain that is perceived in an area away from the site where the pain arises, such as facial pain caused by lesion of the VAGUS NERVE, or throat problem generating referred pain in the ear.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Shoulder Pain: Unilateral or bilateral pain of the shoulder. It is often caused by physical activities such as work or sports participation, but may also be pathologic in origin.