I have recently aquired a 10hh pony, apparently she has been ridden by children, I'm assuming bareback if that is true. The reason I doubt it is when my kids get on her she throws them off, well sometimes she will let them stay on sometimes she wont. The same with leading her sometimes she'll move other times she wont. When I put pressure on her back she steps backwards or in circles clearly not liking it so I'm unsure if its a sore back or not. Do you think she's being stuborn or is it more likely a back problem?