calf muscle need help

I went to a physiotherapist today and he diagnosed me with something about my calf which caused my backpain. He spoke about the mechanics of my body caused my back not stretch so much when I tried to stretch my back backwards so he told me to do some stretches but one stretch I tried and was stumbled by what occured...

click on this link please:

Racewalk.com - Calf Stretches (Page 1 of 4)

the only difference from the picture is that both of my legs are at the same distant position also when i do this the right calf is stretching more and there is a stronger pull is this meant to happen?

Sounds normal to me

The answer to your question "is this meant to happen"? could be yes or no. Much more info required.