I agree with both comments. I could also feel my pulse in my stomach (mostly when laying down). My cardiologist noticed it and said it could be because I am thin but he wanted me to have an ultrasound to rule out an aneurysm. Had it and no aneurysm. I would have a doctor check to be sure.
Are you very thin? Sometimes on a thin person the abdominal aorta can be felt pulsating if you palpate the area.
When do you feel the pulse? Do you feel it when you lay down or constantly? Could it be gas? I would go to my doctor to rule out an aneurysm.