I had chicken pox. Years later I had shingles (basically dormant chicken pox that becomes active again but way nasty). I wish the vaccine had been around before I got chicken pox to avoid the shingles. I probably don't need to worry about them again until I"m officially old, but...
There is now a shingles vaccine as well, I believe. I will be getting it. Yes, you get shingles from having had chickenpox. I know of people who have been fighting shingles for years. It is a miserable disease. Get your chickenpox vaccine.
http://en.wikipedia.org/wiki/Herpes_zoster
http://en.wikipedia.org/wiki/Postherpetic_neuralgia