You describe almost exactly my symptoms. I’ve had it for more than 20 years. Was finally given a tentative diagnosis in 2008 based on my symptoms and EMG. Basically, everything else was ruled out. I know people wonder why I use a walker when I generally walk pretty well, but if you take it away (unless I’m at home with a cane) I stiffen and cannot walk. I retired in 2008 and my symptoms are much better due to less stress but I’m afraid I will never get away from the walker.