Stuttering is thought to be neurological for some cases but currently we do not have a definitive cause of stuttering that applies to all cases. Like sometimes it occurs after TBI. Other kids never grow out of their stuttering phase (as all kids go through short spurts of stuttering when they are first learning language). Most cases appear to be developmental, but sometimes they aren't. They have some ideas of how the brain's structure can affect stuttering but they haven't settled on that being the only reason for all people. The effects/severity of stuttering can be influenced by one's mental perception, i.e. if you are worried about it you are more likely to produce disfluencies. Stuttering is not caused by someone having emotional problems from the start, but stuttering can cause someone emotional problems and those problems can exacerbate current stuttering. It is a vicious cycle. In a weird way I relate to this because I have tinnitus. When I am stressed, my tinnitus is much louder and then the tinnitus makes me more stressed and then it is a cycle. When I am happy and not stressed, my tinnitus is not nearly as bothersome and doesn't even seem to occur as much. I hope you find some peace with stuttering, because I know it is not easy.