You say that your API could save Spotify and Pandora millions per year. Why is that?
Rather than starting by writing lyrics, try exploring different themes and topics through reading, writing, visual art, or anything else that inspires you. Keep a notebook with you at all times. The more you explore art, the more frequently ideas will come to you, and if you don’t write them down, you’ll likely forget. That way, when you start writing lyrics, you can first look at your list of ideas to see if there’s something interesting to start with.