Do most guys do this?

And why do you think he is doing this? He seems pretty reserved and possibly shy...but definitely not flirtatious. He's also friendly and what not. He gave me his number and I texted him. He texted back with a hey. I asked when does he get out of class and he never wrote back. The next day he text's me and I reply. I reply back and then so does he but I say nothing back. Then, a few hrs later he replies with a hey. I reply back and now he is ignoring me. wtf is up with this?