What Causes Severe Stomach Pain, Bloating, Diarrhea And Headache?

hi doctors,i repeat having stomach pain,bloating,diaherra,headache.im on protonix.doesnt seem to help,the pain is unbearable.ive done ct scan,finds nothing..anything i can take for the pain?im trying gerd diet,no results.anyother ideas of what it could be???thankyou so much