HI. You have two different problems. The lump under the nipple should be removed , biopsied. This will help you to get rid of the disease and you get a diagnosis. Second problem looks a bit serious one: Pain that prevents you from eating- immediate fullness, and extreme pain. I would advise such a patient to undergo the upper GI endoscopy asap. This can be an ulcer with a problem at the pylorus. The exact diagnosis is the most important to start the right therapy. Do not waste time in starting the therapy.