He know's someone he cares for is sad, a ex-girlfriend possibly. He's hoping to see this person soon and wants her to know that he will "shine on for everyone" meaning he will be the best thing in her life to make up for how she feels. No matter how bad things seem know he will bring happiness to her. The moon and the stars bring light but if they don't shine they are not to worry cause he will be the light and he never let go of his feelings and he will not give up until she understands.
He know's someone he cares for is sad, a ex-girlfriend possibly. He's hoping to see this person soon and wants her to know that he will "shine on for everyone" meaning he will be the best thing in her life to make up for how she feels. No matter how bad things seem know he will bring happiness to her. The moon and the stars bring light but if they don't shine they are not to worry cause he will be the light and he never let go of his feelings and he will not give up until she understands.