Is the Kingdom of God Within You?

According to the Bible, the central message that Jesus delivered, and one which His disciples later disseminated, was the teaching of the Kingdom of God. While any scriptures in the Old and New Testaments speak of this as a literal kingdom, many are confused on this point, believing it is a kingdom in the heart of man or it is a church presently on the earth today.

Some of this confusions comes from a misunderstanding of Luke 17:20-21 "For indeed, the kingdom of God is within you." So, is the kingdom of God within you?