Hello. It's normal to feel your pulse in your stomach. What the doctors' stethoscope was picking up was the pulse in your mother's abdominal aorta. The aorta is the main artery that carries blood from the heart to the rest of the body. It runs from the heart, down the center of the chest, and into the abdomen.
Many women find out about this when they are pregnant and think they feel their baby's heart beat when it is actually the abdominal aorta. We all have it. It's normal. So literally, that is just your own pulse. Hearing it with a stethoscope at the doctor's isn't something to worry about or your doctor would have told you. The only time to have any worries at all would be if you had deep pain in your abdomen or on the side of your abdomen, pulse near your bellybutton with back pain. Those are symptoms of an abdominal aortic aneurysm. But you don't describe anything like that and it is rare. https://www.healthline.com/health/pulse-in-stomach#abdominal-aortic-aneurysm
Blood flows everywhere in our body, so not sure what you're asking. Did the doctor say something was wrong?