You might want to consider buying a book called The Trigger Point Therapy Workbook. I got mine on Amazon. You can treat yourself using their guidelines. You use a tennis ball and press on the knot (the ball is between a wall and your body) and then move slightly to simulate massage. Keep doing that and the knot will go down. Much of our pain is referred pain and they show diagrams were to look for whatever pain you have. It has helped me a lot. Even my massage therapist uses this book. Here is a link to it.
http://www.amazon.com/Trigger-Point-Therapy-Workbook-Self-Treatment/dp/1572243759
Also, you might talk to your doctor about a muscle relaxer. I was put on Robaxin a few months ago and that has helped me tremendously, also.
Be sure to keep doing your stretching exercises, too, and keep moving as much as you can. There are some stretching exercises in Fibro 101 that you can do sitting at a desk. Hope this helps you.
Sherrine