Is it pleurisy or pericarditis for chest pain in the center of sternum, below left breast.normal 2decho jan2013, chest xray, 12lead ecg, threadmill test?

Describe the pain: How long have you had it? Is it the sequelae of a flu or cold you've had recently. If the pain increases with inspiration or coughing it is more likely musculoskeletal so costochondritis or pleuritic pain is most likely. See your doctor tomorrow. Those tests you're asking about are only necessary if more simple diagnostic steps haven't succeeded in identifying the problem.