I was/am having the same issue ever since my surgery in April. (Mine also had gnawing pain with nausea every time I ate). I was consuming small parts of protein shakes every 3-4 hrs because it settled down and felt better, not eating anything but greek yogurt as well. It would not go away. My surgeon recently did an upper endoscopy which showed diffuse gastritis. I also had biopsies taken for H pyLori still awaiting results. Mention this issue to your team if it continues. Good Luck!