My mare is 14 and she is my main gymkhana and barrel horse. I got her a new saddle because the old one made her back sore. The new one seemed to fit but ever since the old one she lost all back muscle and shoulder pocket muscle. I tried a new saddle pad that didn't work. I heard of shoulder shims and they seemed to work to build muscle in the shoulder pocket but I have no clue how to get the back muscle back do I have to find a new saddle to fit her correctly ???