I Have An Ulcer And A Hiatal Hernia. I Recently

I have an ulcer and a hiatal hernia. I recently had a part of my small intestine removed due to diverticulitis and I had septiscima. now better from that but now I have severe pain in my upper stomach after I eat.. won't go away with meds.; better for a little while but not completely gone. I had this ever since my surgery.
what can I have?