I had a severe case of tennis elbow years ago from fishing, not from casting but from holding a 7' rod in my left hand with a 1 oz. weight and Carolina rig attached to the other end. Big hook sets don't help either. After 2 cortisone shots that didn't help I ended up going through rehab at a Baylor rehab center on I-30 in Mesquite. That was 15 years ago and haven't had any pain since. I highly recommend NOT holding the rod tip high and away from your body, keep your elbow next to your side for support and set the hook with a sideways motion using your upper body instead of just your arm. The ice/heat contrast helps a lot too. Good luck.
Long ago when men cursed and beat the ground with sticks it was called witchcraft, nowadays it's called golf.