I recently purchased a Stearns & Foster Camdenhurst Pillow Top mattress.  The salesman (of course) tried to get me to buy the box spring, to which I said no.  But now (about 2 months after buying) my wife and I feel some back discomfort in the mornings.  We've tried adding a pillow top to the already existing one, but it doesn't seem to help.  So I'm starting to wonder if I did, in fact, need to buy the box spring.  Do I really need the box spring?  If so, which one should I get for my particular mattress?