[John] said to him, “Are you the one who is to come, or shall we look for another?”
Matthew 11:3 #yeshua

I think there are two interpretations of John's question:

1. He was beginning to doubt what he had known his whole life, that Yeshua was the promised Messiah. He was asking for confirmation.
2. He was observing Yeshua's peaceful approach and wanted to know if there was one Messiah or two separate messiah's, one to suffer and atone for the people's sins and one to drive out foreigners and restore the throne.