not the same, adult chickenpox is getting varicella at adult age. shingles is the reactivated form which form dermatomonal blisters and rash.

Not exactly. Zoster virus as a child can lead to pox, flu symptoms, then recede into the immune system for life. If then immune compromised, the virus flares back up in nerve endings and skin, causing pain, inflammation, and can affect the brain.

Getting zoster for the first time as an adult is severe, but rare.