There are a lot of variables that can go into this.
With out knowing if you're having issues with a hot smoke or a hot pipe like brewshooter asked, hopefully this will help out some:
It could be the tobacco (tobacco's with high sugar content, such as Virginia and Aromatics) will burn hotter the those with lower sugar content such as a burley.
A hot smoke can also be caused by how fast you're smoking as well, as well as lenght (short nose warmer versus a long churchwarden).
As well as pipe construction - if you're getting a pipe that's hot to the touch, all the above can be a factor plus how thick the chamber walls are as well as the type of material used for construction (i.e. briar, meerschaum, pearwood, corn cob).
Personally my meerschaum gives me the coolest smoke, smoke to fast though, the bowl will still get extremely hot.