mono sound from stereo earbuds?

You have confirmed that the headphones are not the problrm, right? E.g., they work OK in other devices)

- Try cleaning out/blowing out the headphone jack. Try inserting/removing the plug a dozen times or so. There is a little switch in the headphone jack that disconnects the speaker when the headphone jack is inserted.

Try the following to rule out a software problem

- Check also Settings > General > Accessibility > Hearing. Make sure that the sound balance is not set all the way to "R".

- Reset the iPod. Nothing will be lost

Reset iPod touch: Hold down the On/Off button and the Home button at the same time for at

least ten seconds, until the Apple logo appears.

- Reset all settings

Go to Settings > General > Reset and tap Reset All Settings.

All your preferences and settings are reset. Information (such as contacts and calendars) and media (such as songs and videos) aren’t affected.

- Restore from backup

- Restore to factory settings/new iPod.

- Make an appointment at the Genius Bar of an Apple store. Seems you have a bad headphone jack.

Apple Retail Store - Genius Bar

If not under warranty Apple will exchange your iPod for a refurbished one for this price. They do not fix yours.

Apple - iPod Repair price

A third-party place like the following will replace the jack for less. Google for more.

iPhone Repair, Service & Parts: iPod Touch, iPad, MacBook Pro Screens

Replace the jack yourself

iPod Touch Repair – iFixit

Just a thought, but I suppose you are sure that whatever you are listening to is actually in stereo?

There are several reasons why an audio file might be in mono:

• recorded in mono for artistic reasons (music produced by Phil Spector or one of his followers)
• old recording (Rock albums from the 1970s can sometimes be in mono)
• Many Podcasts are in mono, even music ones
• limitation of the device that was used to record; i.e app on a mobile device
• incorrect setting on the recording device