Is it possible for your heart to make noises that you can hear without a stethoscope?

Yes it is possible: Some people can hear their own heartbeats, but most can't. You can put your ear next to someone's chest and hear the heart beat. High adreneline level such as after a rapid and sustained run can cause your heart to beat fast and hard--pounding--and you maybe able to hear it without anything....So, it is possible...And common.