Your discomfort could be originating from a number of different localized organs in the thoracic cavity. First, it is possible that a gallstone is currently stacked in the bile duct (ductus choledocus). Also, you could be experiencing a liver diseases, or even chest problems. An ultrasound and ERCP (Endoscopic Retrograde Cholangio-Pancreaticographia) can detect disease of the liver, bile duct, pancreas or other internal organ. An X-ray of chest is also recommended. Blood analyses (blood picture, liver status: AST, ALT, bilirubin, cholesterol) are standard procedures in such cases.