Strange pain caused by thinking about heights

Hi,

First off I would like to say, sorry if i'm posting this in the wrong place but after looking through all the forums this seemed to be the best fit. :)

As far as I know I do not suffer from acrophobia (fear of heights) as i'm not actually scared of heights, I can quite happily stand on the edge of cliffs and although I've not had the chance yet i'd really love to skydive, in some ways i'm far less scared of heights then the average person.

But ever since I can remember I have suffered with a very strange pain caused by seeing or thinking about heights, even watching actions films involving heights can bring on extreme bouts of what i can only describe as some sort of electric shocks in my hands and feet.

I have asked dozens of people I know if they have ever had or know of anyone that had suffered from the same thing, they all just look at me like i'm mad.

Does anybody else suffer from this? Is it possible to suffer from a phobia that is only physical?

Would love to know what this is. :)

Cheers