As far as I can understand it, it is genetic and you can't "cure" it. But YOU CAN OVERCOME IT! I feel you. There were times, the really bad times, when I felt I couldn't say a word if I would have been asked to, when my thoughts disappeared and all I could think of was "fuck, here we go again". Sometimes it happens, and it's shit. I was always quite open about it, thanks to a few supportive (even if indirectly - they don't give a fuck) friends and my parents. I had therapy, speech therapy (more like breathe therapy) and I finally overcome my fear of it. I still stutter, it still sucks, I still feel anguish, but it's so much better than before. Meditate, do breathing exercises (breathe with your belly!), whatever makes you feel better, but you should also embrace it. Talk about it to somebody, get out where nobody can hear you and scream something about it! I also never experienced real, free of worries fluent speech (I don't think about it when I'm high on weed and so it gets better, but my speech also gets garbled because of tripping), good on you! (sorry for my probably non optimal english)