"technology is advanced in the US" or "the US is advanced in technology" or else? Are they of the same meaning? Many thanks~

"Where are you from" or "where have you been" or else? Which expression should I use if I see my neighbour coming back and want to ask where does he come back from? Many thanks~

Can I use "what is the book about" to ask about the content or story of a book? Say if someone tell me he has been reading a book, can I say "what is the book about" or are there other preferred sentences? Please correct me for any mistakes. Many thanks.

Can I say "what is your problem" to ask someone what disease she had? My friend told me she was ill yesterday, then I replied "what's your problem", and after a while a started to realize that it may not be a proper response. Any suggestions would be helpful, many thanks.