my friend i suffer the same.
my dad had a heart attack last october and since then everytime i get a chest pain or shortness of breath(from my anxiety)
i panic thinking I am infact having a heart attack..
ive always had anxiety but since my dads incident it has gotten much worse.
rub your chest for a good ten minutes.. and also drink tea!
also i lay partially on my stomach/side .. and kinda grab at my chest and it goes away.
and sitting with <YOUR> knees up or laying with <YOUR> knees up also helps it.