Well, the exact opposite of that would be a waterbed. Depending on what sort of back pain you have and the cause, the waterbed might help you. My back did hurt in the mornings with a waterbed (not badly, the pain went away very shortly upon getting up) and I slept on one for 20 years, but didn't realize that there was a better alternative until my wife came into my life with her Tempurpedic queen-size mattress on a hospital-style powered adjustable bed frame. However... these mattresses are not inexpensive, running well into multiple thousands of dollars, and they are enormously heavy and awkward (200-300 pounds?) and probably difficult to ship to Belize. There are memory-foam alternatives to the Tempurpedic brand for substantially less money, but I know nothing about them. After sleeping on the Tempurpedic for, lets see now, 2012 minus 2005, that's about seven years now, I would go without shoes before I went without the Tempurpedic.

If there is a way to try out a waterbed, you might see if it might suit your needs.

tanstaafl.