I second what Disaster said - I don't think your issue is stuttering-related, but it might point to another disorder. I'm a good writer myself, but it often takes me longer than everyone else to finish writing because of my ADD / ADHD-PI (even though my case is a mild one). It could also just be the way you are, I guess. My dad is a high-level electrical engineer and he's terrible at writing - I often help him write or proofread his reports. We all have things that don't come naturally to us, and that we have to work harder to become good at. Either way, I hope you find a way to cope with it! It could be a good idea to consult someone (psychologist, neuropsychologist, therapist) if it's giving you a lot of trouble. Maybe you could even just go to some sort of writing class (creative writing or other kinds), it might help you develop tricks and techniques.