As I write this response, I find that the above Question was written 11 hours ago. Hopefully, the writer has already gone to a be seen promptly by a physician. Pneumothorax may be due to various causes but the popping of a bleb of the lung, one cause, may recur as later other blebs, previously undetected may break open and allow air within the lung to enter the pleural space around the lung. Acute chest pain which cannot be easily explained is not a symptom to request an answer on Medpedia but the answer should come from your doctor and perhaps promptly. ..Maurice..