Pain ThresholdPainPain MeasurementPain ManagementPain PerceptionEar, ExternalHot TemperatureDiffuse Noxious Inhibitory ControlHyperalgesiaAnalgesiaAnalgesics, OpioidAnalgesicsAnalgesics, Non-NarcoticCold TemperaturePressureAlfentanilWristTranscutaneous Electric Nerve StimulationPentazocinePhysical StimulationFibromyalgiaChronic PainSensory ThresholdsElectric Stimulation TherapyCatechol O-MethyltransferasePain, PostoperativeDouble-Blind MethodLow Back PainBack PainCross-Over StudiesMorphineSp3 Transcription FactorNeck PainSex CharacteristicsPain, IntractableCapsaicinElectric StimulationPelvic PainFacial PainAcute PainPain, ReferredSkinShoulder PainTime FactorsMusculoskeletal PainModels, BiologicalNociceptive PainNeuralgiaMyofascial Pain SyndromesComplex Regional Pain SyndromesChronic DiseaseVisceral PainArthralgiaLabor PainTreatment OutcomeNociceptorsQuestionnairesAnesthetics, LocalDisability EvaluationCatastrophizationFlank PainEye PainProspective StudiesSeverity of Illness IndexInjections, SpinalSciaticaToothacheLidocaineNerve BlockOsteoarthritis, KneeQuality of Life