Welcomeeeeee!
I think that it's dangerous that your chest is hurting, and you might want to consult a doctor regarding that. I hope that you'll be able to express yourself fully and tell the person about your experiences, because these people are there to help you, and it's better for you to rant out to someone as soon as possible. I can also tell that what you're going through is a feeling called nothingness, because you've somewhat become numb and that's not good. There's plenty of reasons for this and most of all certainly stems from some sort of past experience and perhaps some nasty encounters with some unreasonable people. But you can beat this, because the very same way experiences hurt us, they can heal us .
You just have to get yourself involved in plenty of positive things where you'll get to mix around, and generally have a good time... slowly but surely, the positiveness that other people exude will eventually affect you and slowly influence you to be happy and positive. Learning by example certainly applies in this case, for if other people can be happy or joyful, you can be happy the same way.. and there's nothing stopping you. Also, whenever you're feeling bad or thinking negative thoughts, the best thing to do is to treat yourself to something you love (except self-harm) . There's no remedy like some good relaxing times, or some movies with people you care about and cherish. Most of all, don't feel bad for treating yourself- All of us do it when we're going through bad times in one way or another.
You'll always have me, and I want to remind you that you deserve better than to feel like this. Rant to me anytime
I ain't going anywhere, and I'll always be around to help!