How to get same sound in earbuds?

I'm not sure what it would be called, as i'm not that tech savvy in the sound department but when listening to music on my phone for example with earbuds i notice that in some songs, some audio comes in the right bud and the rest in the left… For example the guitar can only be heard in the left earbud and the vocals can only be heard in the right earbud… This isn't a problem except when i can only use one earbud. Does anyone know what this is and how i might change it? I'm using an iphone 5s if thats relevant

It's called stereo and that's how it works. You need two channels. You might be able to get an adapter to convert the signal from your phone to mono so you hear the same thing on both channels.

You're in luck - the iPhone has a built-in "mono" mode, which does exactly what you want.

Just go to Settings -> General -> Accessibility -> Mono Audio. There's a switch for Mono audio, which mixes the two stereo channels together.

See here for a step-by-step: http://www.dummies.com/how-to/content/for-seniors-use-mono-audio-on-your-iphone-4s.html