Small pneumothoraces are occasionally asymptomatic. Symptoms of pneumothorax include dyspnea and pleuritic chest pain. Dyspnea may be sudden or gradual in onset depending on the rate of development and size of the pneumothorax. Pain can simulate pericarditis Pericarditis , pneumonia Overview of Pneumonia , pleuritis Viral Pleuritis , pulmonary embolism, musculoskeletal injury (when referred to the shoulder), or an intra-abdominal process (when referred to the abdomen). Pain can also simulate cardiac ischemia, although typically the pain of cardiac ischemia is not pleuritic.