I can empathize with you very much, i suffer from fibromyalgia, so aches and pains are just part of my everyday. Most sufferers of fibro end up with R.A somewhere in their bodies, its part and parcel of it, unfortunately, my knees have always given me a problem.
Soledad get checked out, that u dont have OOS or RSI as its known or even fibro, always a possiblity, but dont worry too much.
I suppose u try all the heat pads and things available, i find a nice hot spa good, but only have minimal access to those. but with me everything gives only temporary relief.
Have you tried VIOXX, i take it occasionally, but like most it can play up with the old tummy etc, but its one of the better ones, i believe or CELEBREX.
Anyway u are in my thoughts, ongoing chronic pain is hard to live with and effects your all over well being, mentally , as well, its hard not to get depressed when u are constantly in pain, i just have to try and tell myself( on a good day mind u) there are others far worse off than myself on a bad day FORGET IT they are the last words i wanna hear.
Now u look after yourself and anytime u feel low pm me ok.