i have the exact same thing with this girl I like. I feel really weird talking to her as the conversations are really short and a bit awkward at times, but I feel the need to at least be around her. there are some signs that I find good but she seems she can't stay around me for too long she has to move away a bit... it's like one of those sharks that circles around to see the food, she says something, or does something then slowly moves away. she overhears stuff and might jump back in the conversation with short answers from there. but still in a shy weird way. she acts differently around me compared to the other people.
as for fb or YM she never starts convos; when I do, she replies back, we laugh and have fun at each other then she starts sending short answers, fades away and I don't get it. I once asked if I pissed her in any way... she said no. you should do that over fb he'll get it you don't know what to make out of the chats over fb.
try and get time alone with him. my crush's friends seem to be very protective and that scares me a bit. they also feel I like her and I'm wondering why aren't they doing anything.
either ask him on a real date, or ask him to go to the coffee shop with you to buy something. this way it will look casual (better chances to not freak him out ) and you'll get to talk to him. insist if he says no at first. think of some subjects to talk with him, ways to keep him talking if he gives short answers. BUT I believe it's because of his friends... he doesn't want them to know he crushed.
as for the kissing part. he might freak out and say he doesn't like you . then :
A. he either mans up after a while and confesses he actually likes you. (what would be the chances)
B or he deosn't man up, he'll avoid you even more and you'll have to work harder to get him to confess as he already said no.