My chiro uses cold -also called low level laser - for muscle, joint or wherever needed.

I was having some shoulder pain and 10-20 seconds on a few spots - no more pain!
plantar fasciitis -a few treatments on my foot/heal and a recommendation of arch support inserts and much better.

after learning about the laser uses I expanded my searching into infrared and near/far infrared therapies.

which got me interested in that type of heating pads vs the regular heating pads.
The detoxing properties and the deeper tissue penetration effects do make a difference for my RSI/TOS and the associated muscle soreness issues.

I found a lot of info on lasers here-
http://www.laser.nu/