Gi test show diverticulosis and peptic ulcers. hida showed 33%.have diarrhea after eating and headaches. which one could cause the diarrhea/headaches?

Not certain : You have several organ systems involved. A unifying diagnosis would be irritable bowel syndrome and migraine headaches, both associated with fibromyalgia. Do you also have low back pain, depression, chronic fatigue, and restless sleep? If so then fibromyalgia might be your problem. See my chronic pain board on quora.Com to understand fibromyalgia.

Not sure?: Divericulosis can sometimes cause diarrhea/constipation if they become infected(diverticulitis), but it is unlikely to cause headaches. Likewise with gallbladder dysfunction(your hida ef was 33% which is a little low and may indicate that your function is abnormal) as it can sometimes result in diarrhea after eating.

Diverticulosis: Diverticulosis may cause diarrhea, and dehydration may cause headaches. Check blood work for anemia and electrolytes.