I did some jumping today in an AP. Every recovery, my rear end came down on the cantle and I had to quickly reposition to get it in the seat. While doing flatwork, the saddle felt snug, but was okay. After this workout, my back start hurting about an hour later.
Should I get a larger saddle? I am using a barn saddle that the BO said was a basic adult size (17"). I take a 21" in saddleseat and a 16" in Western.