Tight throat muscles as a cause of stuttering?

Tight throat muscles as a cause of stuttering? Hi all, I would appreciate your input on the following issue. My stuttering is highly variable, ranging from mild to severe. In most conversations, I can speak almost completely fluently for the first 10-15 minutes, but as the time progresses, I notice my throat muscles becoming more and more tight which invariably leads to stuttering. Has anyone here perhaps experienced the same issue? If so, is there a method to alleviate this?