Hi there. Rapid heartbeat that comes and goes with slight chest pain and no pressure, loss of breath, trouble breathing etc. is probably nothing to worry about. I have an anxiety disorder and belong to a forum for people with anxiety issues and this is the most common complaint we hear over and over again. Everyone gets their heart checked and rechecked and it is always fine.
The beer before bed was not a great idea - beer is the number one food on the glycemic indesx chart to increase an insulin response in the body - even above straight sugar. When the insulin is spiked then adrenaline response kicks in too. I would gather that is what happened with you.
I am a homeopath and would be happy to refer you to a homeopath near you if you would like - my email is Mscrat@aol.com -