Why do I have to keep changing positions?
Fit is a dynamic thing, but it's not so dynamic that it needs to be changed as often as you're changing it. I'm no psychologist, but I think it's safe to say it's a mental thing. Making adjustments feels better and faster because it feels new for a few rides and then you get used to it. Split the difference of all the measurements you listed and leave it that way for awhile. Be honest with yourself when you feel the need to make an adjustment and realize that once you're within the range of fit that works for your body, no small change is going to make a night and day difference.
If you've been making that many changes for years, you've basically conditioned your mind to react the way that it does and you'll never be happy because of it unless you just leave the fit of your bike alone, unless of course it truly needs to be adjusted. The challenge for you will be determining the difference.
This is not all that uncommon of a condition. I've seen people who do it with bike fit, bikes/components, diet, etc, always expecting the next change to be the one that makes the difference. Just remember that most of it comes down to the rider, especially his/her fitness and skill level, and those things only come with time.