Shingles is usually seen in people who are 50 years and more, but can occur in anyone who has the varicella zoster virus. This is the same virus that causes chickenpox. Once a person has had chickenpox, the virus becomes dormant in the body and can resurface as shingles. The cause for the resurface is not yet known, but it can get triggered by certain factors, such as stress, weakened immunity or cancer. The shingles blisters are painful and can also cause chills, fever, diarrhea and headaches. While the blisters are healing and new ones are forming, the person can spread the virus to a person, who has never had chickenpox.