I'm almost done with my week of taking prednisone---today i've developed some spasming in my side and legs--should i be concerned? what causes this?

May be low K+: A low potassium level can do this. Try bananas or Gatorade.

Reason for taking ?: Not clear at this young age why you are taking steroids. Is it for asthma /other reasons. Did you use steroids before or is it the first time .Prednisone causes fluid retention ,all over the body, more visible in the legs which we call edema which could cause the pain in legs. As repeated use of steroids leads to demineralization of bone with calcium getting away from bones you may have bone pains