I have not, sorry, but have you had your spine checked out via X-ray for stenosis? It's just a wild guess from me, but possibly you have an arthritic or stenosed column that impacts on a nerve when you are (want to) walk correctly erect. I'm out of my depth, again I'm sorry, and I don't mean for you to grab onto my suggestion as if finally someone has your condition dialed in. I'm fishing....