When i feel my stomach beat when i lay down, does it actually match my heart beat?

May be aorta: The stomach does not beat like that. If you feel a pulsation in your abdomen, it is most likely your aorta. If you have not felt this before, there is a possibility it is enlarging. If there is a question of abdominal aortic enlargement, an ultrasound or ct scan is recommended to assess the size and if it it a problem that needs to be monitored.