Is a cat in pain when in heat?

[bunanabebe]

I know this will spark contraversy but I want to know what you ALL think. I know some vet techs on here say they are, but my cat never seems to be. Her meows are more like mating calls and shows no sign of pain.

Think about it, most animals have mating calls. Frogs, wolves, birds. Are you going to argue that those animals aren't in pain, while cats are?

I find this equivalent to the 'blue ball myth'