Firstly, the common sites for duodenal ulcers are the anterior and posterior walls posterior to the bulb, as well as the area behind the duodenal bulb itself. The pain symptoms typically show a pattern. For example, the pain occurs in recurrent, cyclical episodes related to eating, manifesting as sporadic abdominal pain about 2cm above the right side of the belly button, more pronounced on an empty stomach, and alleviating after meals. Sometimes, there is also pain during the night. If the ulcer is located behind the duodenal bulb, it often causes back pain. The main cause is usually an infection with Helicobacter pylori, and eradication therapy can generally cure the condition.