The real lyrics:
My heart burns for you ...

But I misheard them as:
My heartburn's for you ...

The embarrassing moment of revelation:
Thankfully, I discovered the truth before it was too late, although I did think it strange that Martin was singing about indigestion.

Age when I realized how wrong I had been:
16

Misheard by:
Scooby

I think my version is better than the original: yes
I am on special medication: yes