A really interesting read.
I was told to get some custom orthotics, they where the biggest waste of time, they changed how my feet sat in the shoe, so caused more problems than what I had before. I sent them back and had them made thinner etc, but they just didn't work, in the end I sent them back and the bloke was good enough to give me most of my money back.
I'm now trying to strengthen my core etc, I'm going to give the exercises that Clive mentioned ago as well.

