What Causes Sore Abdomen Along With Cramping And Burning Sensation?

I get regular sore stomachs, diahria, cramping and burning sensations. I have tried elimination diets and the only one that seems to help my stomach is a sulphate free diet, alas that cuts out most food groups and i become ill if i stay on it very long. do you have any suggestions? I have had the problem for approx 20 years and it has gotten worse over the years.
Any suggestions greatfully accepted
thanks