Yato was roaming the streets putting up posters for 'The Yato God - Any job for 5 yen' with his number written on it too. While he was walking he didn't seem to be paying attention to his surroundings, and the same could possibly be said to you because you both accidentally bumped into eachother, the impact causing you two to stumble back a bit

Are you okay? Yato asks, seemingly concerned Sorry about that!