OK, but you can say that because you happen to KNOW what it is, and that's fine.

People drop dead too frequently because they wait too long to get help when they have unexplained chest pains that [they think] couldn't possibly be a heart attack.

Wow, thank you so much! I've had this my entire life, but never knew what it was, and never met anyone else who also got it. It's nice to be able to put a name to it.

Oh my goodness. I've had this my whole life too, and could never find out what it was! Wow, the relief I feel right now.