Is it normal to feel your pulse in your abdomen when laying down. no mass present, just a light beat, much like how you can occasionally feel your own heart beating?

Pulse: Yes. Especially if you are thinking and not overweight.

Yes: You are feeling the abdominal aorta pulse. The aorta travels down past the abdomen and then splits into the legs

It is normal..: If you do not have obvious strong pulsations in abdomen ( caution to Aortic abdominal aneurysm ), in young risk free people ( risk is smoking, family history, Mafan syndrome).. than you hear normal resonance of your heart. its stronger if on abdomen in bed and in thinner prople.Vaves of beat transfer to object you in close body contact with. If any doubts , should be examined.