We wish we could help you but, we don't know what the "something in my lungs" is. If you can give us a better description from the X-ray report, we will try to be of assistance. The burping and night time shortness of breath may or may not be related to the X-ray finding.
Because the pain is also in the back i would consider asking your doctor to check for Pleuricy or Pleuritis which is an inflamation of the lining of the lung itself. This can cause alot of pain in the sides of your chest, the front, down in your stomach or even up into your shoulder and neck. And the pain ignites with every breath. it hurts to sit down or get up or even lye down. Definitely ask your doctor about Pleuricy. if gone untreated, it can turn into Pneumonia then you're facing a whole new seriousness of problems. Hope I have been helpful, and good luck!
-Danners