You talk about your delayed take down in another post, so you have an ileostomy.
I'm wondering if you might be dehydrated. When I had my temp ileo I had dehydration problems. One of my first symptoms were charlie horse feelings in my legs and headaches. The worst bout I had in the hospital my entire body felt like a giant charlie horse.
You might want to call your surgeon about this and load up on fluids that combat dehydration, like powerade etc. Maybe you need to have a bag of fluid put in your body.
Or, what Jan said.