Quite subtle this - you can get shingles only if you have already had chickenpox.
The virus that causes chickenpox retreats to nerves located near the spine, where the virus remains dormant until it re-emerges as shingles, often during a period of stress or weakened immunity.
You cannot give shingles to someone else, and you cannot catch shingles from someone with shingles.
However, if you have an active attack of shingles, you can give someone chickenpox if that person makes direct contact with the sores and has never been exposed to chickenpox. Keeping the sores covered under clothing or by plasters will help prevent the spreading of the virus - and chickenpox - to others.
A vaccine, called Zostavax can help prevent an attack of shingles or help prevent a recurrence. Shingles is a nasty and uncomfortable condition, particularly if you get on your head - it would be definitely a good idea to get vaccinated with Zostavax to prevent any recurrence.