Is it more likely for pains and nausea in the stomach to be caused from a hernia wrapped around small intestine, or from diabietis ?

Both are: relatively common reasons. The relative likelihood would depend on severity of intestinal adhesions and degree of control of diabetes. First is a mechanical obstruction, the second is a nerve problem. There are certain tests that can differentiate between the two. Ask for a referral to a GI specialist if your symptoms persist.

Probably neither: Hernia wrapped around intestine make NO sense. DM II may lead to bowel ischemia but this is constamt pain after eating (intestinal angina)