It's in the middle of the night, and he texts you if you're up because he can't fall asleep. This one's pretty obvious. He wants one thing - he wants to get it on with you. He wants to see if you want to come over to his place or if he can go to your place so that you guys can get freaky with each other. Even if you guys don't meet up, he wants to talk dirty with you through texting. He's bored, and he's feeling needy. You should know that this is straight up a booty call. He doesn't think of you as a potential girlfriend if he constantly texts you this at odd hours. You should ignore his text if you don't want to be just his hookup buddy.
What he really means: "I'm thinking about you when I lie in bed without you."
It's perceived as a good thing when a guy texts you good morning or good night text because it means he's thinking of you in the morning when he wakes up and at night right before he goes to sleep. It's pretty generic when he only texts, “Good morning,” because there's a possibility that he also sent it to other people.