It's consistent or paroxysmal? is it related to physical exercise? will deep breath worsen it? how old are you ? have you ever been diagnosed with digestive ulcer?
a few life-threatening chest pain: ischemic heart disease, pulmonary embolism, pneumothorax，aortic dissection. other disease: pneumonia, Ribitis， shingles, Intercostal neuritis，pleurisy（TB ,maybe no fever）Esophagitis, hiatal hernia, esophageal cancer, lung cancer.
you should go to hospital to find out.
At the early phase of pleurisy , it's hard to find out in the X-ray or CT. A few days later, Pleural effusion may appear on the chest radiograph.