Why doesn't my right headphone doesn't make sound?

I have the iPhone 7 EarPods (not the Bluetooth ones ) They were working just fine until one day I realized that there was no sound coming out of the right side. I already cleaned it but doesn't work. How do I fix this?

It's broken

Buy a new set

Test the headphones with another compatible device. If they still don't work, then you need to buy yourself a new pair of headphones.

Assuming the problem really is with the headphones and not what you have them plugged into, there's probably a broken wire or connection somewhere - most likely inside the plug or inside the headphones.

Unless they're really expensive headphones (or you have the time, skills and tools needed) it's probably not even worth trying to find the fault. Bin them and get a new pair.