I didn't read what other said so I am sorry if I repeat...
Shorten your sturrups (they should hit your ankle bone when you leg is relaxed)
Try a egg but snaffle or a slow twisted d ring snaffle
The reins should come up out of your thumbs ... google it I am having a hard time explaining it haha
Make sure that the saddle isn't punching his withers
Good luck! :)