NOTE: Making your volume or music louder can damage your hearing.
Volumes are limited by phone manufacturers by local laws to protect our hearing. However, there is a way to boost your volume.
Download an app from the Android Market called Volume+ (Sound Boost). You can also download an app called Volume+ Free which requires no upfront payment to download and use.
The downside of this app is that you need to root your LG G2 for it to function properly.
Watch the Video Below for More Info