Is Zechariah 13:7 talking about the Messiah or is it about the false shepherd whom God strikes in Zechariah 11:17 or perhaps the false prophet in Zechariah 13: 1-6?
The shepherd of Zechariah 13:7 is the Messiah. I know this for sure because in Matthew 26:31 the inspired gospel writer Matthew tells us that this prophecy was fulfilled when Jesus was arrested and his apostles fled.
Besides, Zechariah 13:1-6 is not talking about “a prophet.” There is no single figure being prophesied in Zechariah 13:1-6. This is not so much a prophecy as a warning to not listen to false prophets. Once Jesus comes, bringing in a fountain for the house of David (I assume that this fountain is baptism and Christian salvation), prophecy will soon cease. We are no longer to listen to false prophets, Jewish or otherwise. We have the scripture, including the New Testament, as a source of truth now.
Zechariah 11:17 is about something completely different. This is a foolish shepherd. It is a “worthless shepherd.” It certainly is not the Messiah! This may be a reference to the Saducees or the Pharisees who were false shepherds for the Jews (see Matthew 23). The context of Zechariah 11:17 is the Jewish leaders to whom Judas betrayed Jesus for 30 pieces of silver. This is part of a prophecy about the betrayal and execution of Jesus, and these shepherds are not good people at all!