Because you ride English I would guess that you may be trying to ride your western stirrups the same length as your English stirrups.
Just yesterday I had my stirrups adjusted farther up from riding my colts and forgot to let them down when we went to go push cows off the mountain. After a couple of hours my feet were going numb. I had hop off let my stirrups back out and they were fine for the rest of the day.
I agree with posting a picture so you can get a better answer. Posted via Mobile Device