I don't understand how vegetable juices would help pain, but hey - if it helps it helps!
broomhilda, you'll need a juicing machine for this task, and it's fairly messy. It's kind of like a weird blender, and removes the non-soluble fiber from fruits and vegetables, leaving the soluble fiber and liquids behind. When you drink the juice, you get all the nutrients because they haven't been cooked away. You'd be surprised at just how much fiber is left behind after a juicing session. That's where the mess comes in. LOL!
It's also suprising how sweet certain vegetable juices are. Of course, carrots and beets are naturally sweet, but even broccoli isn't bad. Do a google search on Juiceman+Juicer - there should be a lot of info out there for you. I got mine several years ago when I could no longer tolerate solid foods, and have used it all this time. I seem to recall that the "juiceman" was the first high-selling juicer, and the man who designed pushed for juice fasts to achieve optimal health. I couldn't speak to the effectiveness or safety of fasting, but it's certainly good for maintaining good nutrition in a natural way instead of relying on pills.
Living in the Republic of Texas minus a gallbladder, a couple of cervical discs, appendix, uterus, and 18" of colon; but still alive and living with my husband, 2 dogs, 1 cockatiel, 1 quaker parrot and 2 gold fish.