my new pony is now pulling his head out to the side and moving his body in towards the centre of the arena and he'll through his head. I cant even do a lap of trot or canter with out slamming to a halt and trying to move inwards to the centre of the arena. We bought a new saddle and is a good fit so the tack seem to be no harm. Any tips? Its really fustrating and he constantly tried to run off into a trot or canter so im constantly pulling him back and doin hip over cues.