Lynn, shingles is caused by the same virus that causes chicken pox. If you have had chicken pox, you carry the virus (herpes Zoster) in your body. Some breakdown in your immune system triggers the shingles to break out, along a variety of possible nerve routes. Early treatment with an anitviral, like Famvir, is imperative. Often steroids plus analgesics are prescribed as well. It is important to begin treatment within the first three days of the outbreak. There are wonderful articles available on HealthlinkUSA.