When you hear music through headphones or the included headset with your Samsung Galaxy S5, then it may be that the music is heard from only one of the two headphones. If you have ensured that the headphone has no defect, then you should consider the following setting in your Android Lollipop operating system, which leads by an incorrect setting that the music is heard from only one of the two headphones.
The setting is called "audio balance". With this option you can set the balance of audio on the Samsung Galaxy S5, for the two headphones.
And the option "Audio Balance" on the Samsung Galaxy s5 can be found in S5 Android Lollipop here:
Open the following sub-menu from the home screen of your Samsung Galaxy S5:
Menu --> Settings -->Accessibility --> Hearing
You can now click on the "Audio balance" entry, so that a window opens in which the audio balancefor headphones for the media players can be controlled. Insert here the lever in the middle to achieve a balanced audio while listening to music with headphones. Finished!
When you now listen to music with your Samsung Galaxy S5 via headset or headphones, the music is balanced again. Also check whether the option "Mono Audio" is disabled in the same menu If not erase the hook in the checkbox.
Now you know why your Samsung Galaxy S5 plays the music only on one of the two headphones and how you can disable it in Android lollipop.