I find procrastination is a symptom, not the actual problem.
The very root of the problem is that I'm either faced with something I just don't want to do or can see that the NEXT thing is something I really don't want to face.
Yes, this. I have no problem working when I'm excited about the work. If I'm not excited, then it's usually some extra-curricular problem or the work is not the kind of work that inspires me.
There's a difference between dealing with a little boredom or muckwork in a project (there's always some of that) and the sort of relentless, day-long, can't do anything procrastination the OP describes.
Sure, we all have those little jobs we don't want to do... But if you find you just can't get anything done for days at a time, it means your subconscious is trying to tell you something. You'd be wise to try and figure out what, and take steps to address the underlying problem.
The difference between those who do and those who bemoan not doing is motivation. The Hemingway Trick is a simple way to give yourself the initial motivation. Then again, you might just be lazy.
The very root of the problem is that I'm either faced with something I just don't want to do or can see that the NEXT thing is something I really don't want to face.
It usually means I need to do some introspection.