Maybe it's words of encouragement to someone called 'Herbert'. Or perhaps - given that in the expression "You go, <noun>" the noun is usually "boy" or "girl" - it is a play on this (in which 'herbert' is a mild/jocular term of abuse [in Br Eng], as in the expression 'spotty herbert').
As Bob said, it sounds as if "Herb" is a man who is being encouraged by someone or some group. "You go, Herb (or other person's name)!" or "Go Herb!" are common shouts of encouragement in AmE.
If you have a question about the English language and would like to ask one of our many English teachers and language experts, please click the button below to let us know: