Nerves are everywhere in the body. They run your organ systems, constrict or dilate blood vessels, run your heart, in addition to feeling outside pain.

If damage occurs to the nerves in the system that runs your organs this is called dysautonomia.

http://en.wikipedia.org/wiki/Dysautonomia

This can come from infections, toxins, diabetes (most commonly),
low B12 status, many things like that.
When the stomach is involved, it is called gastroparesis.
Diabetics with severe neuropathies often get this eventually if they do not keep tight control of their sugar levels. Gastroparesis is a later development of neuropathies in general, not an early sign.

Some dysautonomias may be due to mitochondrial failure from drug toxicities (statins do this) or genetic errors of metabolism in the nerves. Some present with blood pressure swings, fainting, etc.

You can get pressure in your midriff area from gas building up in your stomach and intestines. It is a simple cause, and may be due to dietary intolerances to gluten, or fructose. Some people with Candida infections have this symptom. (following use of antibiotics). Gall bladder problems also generate gas in the GI tract commonly.

There are over 100 causes of various peripheral neuropathies. You'll have to come to our PN forum and read the subforum.
I personally believe that infection, and prescription drug use are major causes. Followed by toxins and vaccines. It seems that over the past 10+ yrs I have been on PN boards, that the patients show up now younger and younger. It used to be an older senior citizen type problem, and now generalized to all age groups! This implies to me something in the environment, doing it.

You will have to become a detective to find your answers. And keep in mind that some impaired glucose tolerance does not show much in the way of high sugars in the beginning. But the process can be working on your nerves at that stage. I'd request a fasting INSULIN level, to show if you are becoming insulin resistant and hence on the way to diabetes in the future.