Speaking from 4 years of harsh back-pain experience, I can tell you the best home remedie, above painkillers or massage or whatever, is taking a nice hot bath (as hot as you can comfortably be in).

otherwise, I'd suggest joining yoga, its' more of a long-term approach to healthy muscles, seeing as it makes you much stronger and more flexible. though after one class you'll feel better.

oh, also sitting at the computer is probably the worst thing for you.