Most major music charts incorporate radio as a primary ranking metric besides streams and sales. The more a song is played across various radio stations, the higher its potential for climbing the charts. Airplay also plays a crucial role in determining the longevity of a song on the charts.
Not really. The artist has to pick a track to "service" to radio. That just means a track is submitted to radio personnel and then usually they decide to play it or not. It's the primary way to be heard by a diverse audience.
Shazam uses its music recognition technology to identify and rank music being played on over 40,000 radio stations worldwide. That includes both radio stations who still transmit music the conventional style and internet radio stations. Shazam often sends its data to radio stations to determine the popularity of a song and can have an impact on whether a song should be played. (Shazam is owned by Apple.)
You can Shazam a song by downloading the mobile app on the App Store or Google Play, then playing the song and opening the Shazam app to identify it. If you're on an iOS device, you can also play the song and use the Shazam button in your Control Center. Both options work.
Make sure to sign up on the RateTheMusic website to be sent surveys to your email that help determine what songs can be played on radio stations. For example, you can sign up for the Rhythmic Radio survey and you'll see "Lover Girl" in the survey. It will ask you 3 questions—make sure to put yes for "familiar with the song", like it a lot for rating, and no for "tired of hearing the song".