I have the same problem but I was able to find out what was causing it. My doctor did a bunch of tests and told me that I have a severe sensitivity to gluten and that I might have celiac disease. I cannot stress enough that you need to get checked for this!! My doctor said that the gluten sensitivity has caused so many of my other medical difficulties in the past including Irritable Bowl Syndrome, Depression, Weight Gain, and Panic Attacks. If this is what you have, getting tested could change your life.
Have yourself checked for the presence of H. pylori. Many with the bacteria find that they have 'sulphur' burps. Problems with the esophagus and gallbladder can also result the same symptoms.