Sound only coming from one side

Hi Liv123-,

Ensure the Left Right Stereo Balance slider is balanced in Settings on your iPhone. This will help to make sure the sound comes from both sides of the headphones. Check that out here:

Adjust the mono audio, balance, and phone noise cancellation settings on iPhone - Apple Support

1. "Go to Settings  > Accessibility > Audio/Visual.
2. Adjust any of the following:

• Balance: Drag the Left Right Stereo Balance slider."

If the issue persists, test the behavior with a different set of headphones to help isolate the sound issue. If the issue is no longer present with another set of headphones, then seek service for your headphones. You can see that outlined in the following article:

If your headphones don't work with your iPhone, iPad, or iPod touch - Apple Support

"If you can't hear any sound or if only one side of your headphones works

1. Adjust the volume with the volume buttons on your iOS device or use the Volume slider in Control Center on your iPhone or iPad. 
2. To see if you need a replacement, try a second pair of headphones. If the second pair works, contact the manufacturer of the initial pair and ask if you need a replacement. If the second pair doesn't work, contact Apple Support."

Kind regards.