I get nausea, bloating, gas, abdominal cramps and fowl smelling burps after I eat any pork products for years now. What can cause this?

Nausea/abd pain. With your current symptoms, two most likely causes are gallbladder dysfunction or gastroparesis ('lazy stomach', your stomach is not emptying food into the small intestine properly). Should discuss your current symptoms with your physician for further diagnostic tests, which can be quite simple.