character change

Question
Hello;
I purchased a horse in January. He was shipped from California to NJ. I bought him as a green horse. I am an experienced rider but I am confronted with a problem that I never had before. The horse is a four year old. For the past two months I have been working in the round pen and teaching very basic transitions and softness. He was doing fine until one day he refused to lope and started bumping me into fences. The bumping me into fences has gotten worse now he crashes me into fences. If I start him out walking in the center of the arena and all I ask is to go forward he side passes me into the fence. If I kick him to get away from the fence he will crash me harder. He also will crash into jumps in the arena without any care for himself. what should I do

Answer
Dear Tony,
         He may be testing you to see how much he can get away with, and definatly must have gotten away with alot from his past owners. The thing with buying a horse you have never seen or riden before is there tempers are unknown.
michelyn