calf cramps while in a cast

Shouldn't you be asking this of your doctor?

In any case, if it is a "cramp" rather than a physical ache related to the injury...try a bit of quinine water. Just a shot or two. The quinine water has made a significant difference for me in leg cramps.

Don't over-do it. Quinine, is not something to over-use.

You need to find out why there is pain in the calf.

It COULD be just muscle cramps. I had a cast from my knee to my ankle and had cramps, just due to my new walk, with the foot position being different. I also had back pain due to having a different gait.

I think you need to consult your doctor about this.

There is actually a psychological phenomena where the brain thinks that a paralyzed/immobile appendage is immobile due to cramps. (It happens to paralyzed veterans a lot.)

The therapy for this is a mirror box where you exercise the other leg/hand/foot/arm, and it's mirror-reversed to trick your brain.

I'm not saying this is the source of the pain; I'm just throwing it out there as a possibility.

When does the cast come off?

A tablespoon of yellow mustard can do wonders, as well.