My speech therapist says when you have a disposition you only need a trigger that start the stutters. My das also had a stutter so I always have that disposition. Mine started after a really stressful time. It got better. Got a stressful time again, it is worse now. However the origin isn't really the point. The point it what to do about it in the future. That's why I am in speech therapy now. It's really something different if you analyse your symptoms for yourself or a professional. I hope you find your solution as well:)