Do most guys do 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?