AspirinSensitivity and SpecificityPainChronic PainPain ManagementPain ThresholdPain, PostoperativeLow Back PainPain MeasurementBack PainPlatelet Aggregation InhibitorsAnti-Inflammatory Agents, Non-SteroidalAbdominal PainNeck PainPain, IntractablePain PerceptionPelvic PainFacial PainContrast SensitivityAcute PainPain, ReferredTime FactorsReproducibility of ResultsDose-Response Relationship, DrugShoulder PainPredictive Value of TestsProspective StudiesMusculoskeletal PainTiclopidineThromboxane B2Cyclooxygenase InhibitorsTreatment OutcomeAnalgesicsPlatelet AggregationROC CurveSalicylatesInsulin ResistanceDrug ResistanceSensory Thresholds