I have being researching about this question and found some information about this.

It’s really had to explained and express how you feel to others. Song lyrics are a lot easier to express how you feel. The back round sound track  are made to help you to express your feeling and to show your love of music. While researching I found out that song are not just for fun but to tell people how you feel.

The study found that music that creates pleasurable emotions lights up the mesolimbic pathway, the reward bit of the brain that gives us happy feelings. … It appears that music has a unique power to witch image or emotional memory.