chiropractors do a good service for peoples back but btw, you can do the same manipulations to yourself. it is very similar to how you crack your knuckles.
also, btw, chiropractic treatment will eventually leave you with a nervous defect in your spine and shoulders.
essentially if you go to a chiropractor more than a few times you are hooked into it for the rest of your life. you'll be lucky if you dont have to go more than the recomended 'every 6 months'
just my 2c