Bile RefluxAbdominal PainDuodenogastric RefluxGastroesophageal RefluxBileBile Acids and SaltsPostgastrectomy SyndromesGastritisBarrett EsophagusPainEsophagusVesico-Ureteral RefluxAnastomosis, Roux-en-YBiliary Tract DiseasesManometryBile DuctsStomachGastric JuiceGastric MucosaEsophagitis, PepticPyloric AntrumPain ManagementChronic PainAbdomen, AcuteDyspepsiaHelicobacter pyloriMetaplasiaLaryngopharyngeal RefluxPain ThresholdBilirubinHelicobacter InfectionsPain, PostoperativePain MeasurementBack PainCommon Bile DuctEsophageal pH MonitoringPain, IntractableLow Back Pain