Pulmonary embolus, pneumothorax, pleurodynia, pericarditis, atypical MI, hyperventilation, hiatal hernia, esophagitis, esophageal spasm, herpes zoster (pain may precede rash by 2–3 d), aortic aneurysm, breast lesions, various bony and soft-tissue abnormalities (rib fractures, costochondritis, muscle damage), perforated ulcer, acute cholecystitis, pancreatitis