Many people who have suffered with pain, muscle strains and so on, swear by the infrared heating pad. As the name suggests, this device gives off heat in the infrared range. Infrared is the same part of the light spectrum that the sun uses to deliver most of the heat to our planet - it is also the heat you feel from a light bulb.
There are several variations on the heat pad - a traditional low tech version would be a hot water bottle. Even something as simple as this radiates a heat that many people find very soothing.
Those pads working in the infrared range and running from mains electricity can provide a more controlled heat - at a better temperature of under 50 degrees Celsius that can be maintained for a respectable length of time.
The key to the effectiveness of such heat pads is the depth that the heat can penetrate beneath the skin. Not everyone agrees about their effectiveness, but many users have found them really helpful to their recovery or the way they deal with pain.
Since there are many products that are similar at various prices, it is difficult to know where to start if you want to buy one of these devices. You could ask the advice of your physician who should be able to tell you a little about them or point you in the right direction. If you start your research with one of the market leaders like thermotex infrared heating pad then you will find a lot of useful information on which to base your decision.