Audio not coming through headphone jack?

I have a MacBook Pro 13" from 2010. The sound generally comes through fine, but when I plug in speakers or headphones, sound only comes through one speaker/earbud. This is a very new problem.

Is there any way to fix this without replacing the jack?

Have you checked the balance in Sound preferences?

I checked. It's right in the middle.

MBA - Headphone jack problem

Same here, I've had a problem with my MBA 2013 (OS X 10.9.4) headphones jack too for that last couple of weeks. Internal speakers work fine, but plugging in apple or other headphones will only give audio in the left channel.

I've tried all the other tricks, ie checking the balance in sound output etc. and checking if my headphones work on other devices. Can anyone figure out what's up with this?

Try wiggling the headphone plug gently and\or slightly pulling it out a bit to see if the right channel begins to work again. You could also try using a strong toothpick to insert in the jack and move it around a bit to see if you can restore right channel sound. If nothing else works and MBA is out of warranty, buy yourself a pair of wireless BT headphones.