You have a lot to learn. First of all, what she SAYS doesnt mean jack shyt. She could just be bored, or testing to see his interest level. Or maybe she wants something from him (And I dont mean HIM.)
Second of all, women dont like to solve problems. They like to bytch about them. Meaning, if she misses someone, she would rather be sad and talk about it, than actually take the time to go see that person. My ex does this shyt all the time. (We're FB's after four years broken up, btw) She'll call me,a dn we'll make plans, and she'll flake. So I wont call her back. She calls me two to three WEEKS later to hang out. Then she'll tell me how much she's missed me, and how she's been fantasizing about me banging her for the last two weeks. Now, shy didnt she just call me then? Cuz she's a FEMALE, and she makes NO SENSE WHATSOEVER, and her words mean NOTHING.
Third of all, the word 'miss' can have all different levels. It doesnt mean she misses him enough to go SEE him. If she missed him and wanted to see him, she wouldn't have said "I'll think about it." (Translation: "No I wont see you, but I will be thinking about seeing you.) Providing that wasnt said in a joking manner that is. If she was serious, that means she doesnt really want to. Which raises the question: Why did she say she misses him? Draw your own conclusions.
But, throwing your phone across the room over that was a pretty chump move. You cant let women get to you like that, and if you ever SHOW them they get to you, you're DONE.
Women need us to be an emotional ROCK, which is a catch 22, cuz they complain about guys being insensitive, yet if we show any emotional weakness, her respect for us dies.
I cannot stress this enough. NEVER "REACT" to a woman. Take your own action, but dont let anything a woman does influence our behaviour, positively OR negatively, but especially negatively. At least hide it from her with your life. That is the most important DJ concept there is.