Not sure if this is the right place for this but here goes. I have been given conflicting advice by so many people I finally decided to ask the wise sporty mn'ers. 
For a long time I have experienced calf pain when walking, this is mainly when I am wearing flats but is also pretty bad when I wear Fit Flops, so not just confined to completely flat shoes. It's difficult to describe the pain; sort of like a severe cramp in calf muscles which builds and burns and generally feels like my calf muscles are going to ping apart, getting worse until I have to stop walking and lift each leg until the pain stops. It's terribly painful and I generally have a high pain threshold.
People have told me it is because I have flat feet. I've looked at my feet in a mirror and I don't. I have a visible arch.
So, what is causing this pain? What can I do to prevent it? Help! I can't keep catching the bus!
TIA 