How can I go about licensing music for a commercial for my business?
You can start easily by going to Hfa or the Harry Fox Agency at this site
This organization issues the licenses necessary to use music for many things including your issue. You can open a free account and search the data base for the song or music you would like to license and then you will have to apply to state how you will be using the music and then pay the licensing fee to the songwriter through hfa. Costs vary depending on the use and can be $50 and way upwards but you can sure find it all out on this website for music licensing.
Easier than most think.
I hope this helps.