It could be erosive GERD. Acid from the stomach can damage the lining of the lower esophagus and cause a lot of pain symptoms. You'd want to see a gastroenterologist and have them do an endoscopy to see the lining of the esophagus to check for erosions.
Or you could try taking an over the counter PPI medication for a week and see if that helps, something like Prilosec or Prevacid 24HR. Depending on how deep the erosions are, it could take several weeks before you'd notice much improvement from the medication, since that type of damage heals very slowly.