HomeGrownScales is more than likely right, i have a big female that i just got on tuesday that is acting the same way and its because i just got her and she needs time to settle in. He's stressed for some reason, i suggest following what HomeGrownScales suggested.
Edit: Also ambient temps are a little low, and a hide on the cold side would be good so he can thermo-regulate. They will choose safety over temperature so its good to give them the option by giving them two hides.