I have only ridden for seven years, but I have a nack for stubborn horses. I am the one to ride them at the barn. Be patient with him. Try not to spur and whip to much, that may make him more stubborn. When you feel him becoming stubborn and not wanting to move foward let the reins a tad longer than you would normally, but make sure you have control. Loosen your grip as well. Also, if you can make him go in circles in every corner. That is good for both hyper horses and stubborn unmoving horses. I know it may be tricky in a lesson. If he stops before a jump or acts up going over one, make a harsh clicking noise and urge him, squeeze him as hard as you can, make sure he knows you're the boss. ALso, think happy, moving forward thoughts... sounds crazy... it works though! Hope these tips help. Good Luck!!!