The grammar used in the lyrics of a song may be quite different from that used in written language. For example, perfectly correct grammar can sound out of place in a Rock or Blues song, as these styles are based on a language tradition that has always included slang.
This is demonstrated in the following song, where "comin’" is used instead of "coming". You could also change the word "been" to "bin". Being aware of the language commonly used in a particular style of music can help you sound more authentic in any genre. Listening to a wide variety of music will help you with this regardless of the style you like to sing.