No output in right channel audio headphones The right channel output cuts off and on when using headphones. The laptop speakers work fine.

I have tried 3 known working headphones, a USB headset (connected via USB not using the audio jack), cleaning out the audio jack, nothing fixes the problem.

The only fix I have discovered so far is twisting and moving the cords for all the headphones I have used, only problem with that is all these headphones work fine with other devices such as a PS3 a different PC ...
It sounds like this is an electronics issue. Its probably a single wire (the one wire that carries the right channel sound). 

There is little that you can do about this unless you know how to solder/feel comfortable doing this repair yourself. 

I would suggest checking if your computer is still under warranty and if it is having apple take a look at it. That should likely be covered.