Hello I believe I can help you with your concern
I am sorry that you have been dealing with this issue of stuttering for so long, but congratulations on recently completing your Master's degree, that is quite the accomplishment.
Since it sounds like your stuttering is not caused by a physical defect or an auditory processing issue because it occurs at different times that are usually more stressful, it appears to be the result of a Social Anxiety Disorder.
This would also explain why the Lorazepam is effective for you, why it occurs when you are more stressed (anxiety and stress both have the same the physiological symptoms, such as stuttering) and why you were shy as a child and avoided social situations.
The good news is that Social Anxiety is treatable with a high success rate through the use of Cognitive Behavioral Therapy (CBT). This is most beneficial and evidence based treatment for social anxiety disorders.
What is going on in your subconscious and consciousness is that you are having negative thoughts, most likely about social situations, that causes you to increase your anxiety and thus causes you to stutter. So the goal of CBT is to change that negative thought process into a more positive and plausible one to lessen the symptoms that you have been having.
So this link may help you, it contains a technique I use with patients called a thought record. It will help you keep track of any negative thoughts you have. You put the negative thought on paper, the emotion accompanying, the evidence to support it, and the evidence against it. Then I want you to come up with an alternative thought for the situation (more positive and plausible). This will help you change your way of thinking to be able to think more positive and not automatically go to a negative type of thinking.
In addition this de-catastrophising worksheet is also helpful to use before any event or occurrence that you feel will be very stressful for you.
Now if you choose to see a CBT therapist, they will use worksheets like this as well as something called exposure therapy, which will expose you to anxiety provoking situations in a controlled environment to allow you to process it slowly and adapt. Gradually the level of stress and anxiety that provokes your stuttering will be increased until you develop a tolerance and are no longer anxious or stressed from these situations.
By the way stuttering is not an uncommon symptom of social anxiety disorders. So no need to feel that this is atypical behavior at all.
Thanks. CBT would be something that interests me. Ideally I would like to not have to take lorazepam but since it has worked well for me in the past without any side effects, I think it may help. I just get wary of all the talk I read on forums about addictive and dependency issues. Would it be possible to try CBT with medication or is CBT a therapy that is used without any meds?