Sounds like your stomach is bloated with gas, that distends it and causes the pain and nausea. It can happen because of certain foods or anxiety. As skyler390 mentionned, sip on something warm and try to apply a warm compress over your abdomen. I get that a lot due to possible gastroparesis (not diagnosed, but still) and I take domperidone to help when I feel like that (it empties the stomach faster). Maybe you ought to speak to your doctor about that and see what your options are?