What stops me

If speech has to be effortless, what is the prior effort about and how are you making the effort?

Reading the articles on stammering sites it is clear that attention is focussed on fear of stammering. So investigating these fears is a good way of starting, and writing the findings down is the only way of separating the ingredients if you are working by yourself.

Having identified them are the fears reasonable or are they fears that have no real substance? Do other people actually care about your stammer as much as you think? What is your evidence?

However, concerns about stammering don't actually deal with the original situation from which the stammer emerged and how the ingredients are being brought together ie The 'why me?' question. What was going on in your life when you started stammering. If you were at school or before hand could you have copied someone elses stammer? What were the school or family circumstances going on when you began stammering?

Other suggested questions:

What am I thinking when I stammer?

What is the effort attempting to solve?

Am I making the effort as a child would or as an adult?

Am I seeing the world, in terms of speaking, as a child or adult?

Pick a single episode where you stammered and investigate that, otherwise it is too easy to theorise or rely on myth to explain your thinking. The theory and the myth will have major errors. It is your actual thinking that is important and if you can't be clear about that then try to guess but be clear that you are guessing and treat the result tentatively.

The judgment should follow the description and don't be in too much of a hurry to converge on the answers.

If you don't write the answers out you will be doing yourself a disservice.