Third time

Zum bucked me off for the third time yesterday. There was no apparent reason why he went into a panic, turned around, bucked me off and ran away. I landed on sand as I was riding in a wash. I didn’t break anything but I think I fractured my tailbone. It is very painful. Luckily, a mountain biker found and caught Zum on the trail. Zum was fine. I couldn’t sleep last night because of the pain but also because I don’t know what to do to fix Zum. Can a horse that bucks and runs away be fixed? This photo was taken right before Zum bucked me off.