I have a pulse in my stomach and had it for a while now it sometimes comes with pain other it don't, could you tell me what it is?

Aorta: The aorta, which is the main vessel for blood leaving the heart, traverses the midline of the abdomen before splitting into to two smaller vessels to carry blood to the legs. The pulse of the abdominal portion of the aorta is easily felt in most people. The pain may be unrelated to your aorta (such as intestinal gas) in the absence of lightheadedness or radiation of pain to the back or legs.

Aorta: Most often, a pulse felt in your abdominal area, especially if thin, is your abdominal aorta pulsation that you are feeling. This is a normal occurrence in the majority of cases. If concerned, let your Dr. know what you are feeling and they can confirm the issue, especially if you are having pain in your abdominal area (that may or may not be related to the pulse). Best wishes.