I have found this helpful when I have tension stemming from poor posture (hunched over a 40-count silk gauze piece), stress, and so on. I think you might like it, too. (I also have a file on how to make a cold pack).
Put 2 cups of uncooked regular rice (not Minute Rice) into a tube sock, the leg from a pair of panty hose, or a homemade tube of fabric.
The filled tube should have a lot of "give" in it so it will drape freely, rather than be stuffed tightly like a sausage.
Heat the pack in the microwave for 1 minute. Lay it across your shoulders and around your neck. Ummm!
As you get the feel for the amount of rice you used and the thickness of the tube relative to the amount of heat your microwave produces, you can experiment with heating the pack longer. Be careful not to burn yourself! Don't use it against bare skin.