Thanks guys, I feel worse now because if he was scared and Im 99% sure he was scared why wasn't I awake to notice this. In my lessons I ride a horse who freaks at a hose or anything when he is in a scared mood. So I should have been awake. I could have helped him ride throught it. I mean a car back fired right next to Chinga and he didn't freak also my friend touched an eletric fence and screamed really loud right next to him and he didn't freak.
I think it might of been the neighbours dogs but I used to ride him at his old owners place and there were two dogs that I used to ride him with there and he didn't seem to mind.