Direct warmth has been shown to be extremely effective in relief of pain especially muscle soreness, tightness, and spasming. I have used the hot towels and electric warming pads for treatment of pain, but recently discovered a couple over the counter patch products that I find work very well. These heat patches last longer and stay in place with more comfort than your typical hot wrap or electric warming pad that is used for relief of pain. In addition, they do not require a power source to activate or keep them warm. I use these for treatment of pain at least once a week.
The first is a very thin and sticky patch that uses capsaicin, the active ingredient in chili peppers. This provides a sustained and direct warmth to the skin and increases circulation in the area under the patch. These last for about 7 hours and can be purchased at most pharmacies over the counter. They cost about $1.50 each. When I have muscle spasms that involve micro twitches of muscles in my back and side rib area, I find these patches can alleviate the symptoms in about 20 – 30 minutes and maintain relief for 6 – 7 hours. I do not need to take a muscle relaxant or pain killers if the patch works. It provides a warming sensation on the skin that is different from a patch or hot towel. The best way to describe the effect is that the patch indirectly “heats” up the area by increasing blood flow to the surface and then to deeper levels of tissue. One problem is that if you have sensitive skin these may cause some itchiness. Also, they will feel very hot if you have one on your back and you sit down in a hot car seat. In the beginning you need to try them out for a short period to see if you experience too much burning, itchiness, or rash.
The second product is a clever derivative of those chemical warmers that skiers and winter outdoors types use to stave off numb fingers and toes. These are composed of a powdery chemical in a cloth-like pouch. The pouch is sealed in an air-tight plastic package. Once you open the plastic the chemical powder (which is in an air permeable cloth that keeps the powder off the user) is exposed to the air and as a result of this the powder gives off heat from 8 to 12 hours.
The patch version is just the powder distributed in thin pockets on a patch with sticky areas allowing it to stay where you put it (on your neck or lower back, for instance.) The resulting warmth is much like a hot towel or electric heating pad and lasts about 7 to 8 hours. If I have tight muscles that get sore I find I can stop the spasming process early by using these patches. I find if I get the patch on soon enough, I do not have to take extra medication or a muscle relaxant most of the time.
Above is a box of links to some of the products I use. You may want to try them in a single pack before buying in bulk. If you can find them at a drug store on sale and your state sales tax is not high, you can get them for about the same or less than Amazon.com Best of luck in your search for relief of pain.