Let me be clear. This is a dangerous situation for both of you. I am not going to offer you ways to fix your horse as I don't want to be responsible for anything relating to you.
Therefore my advice is simple: Get a trainer and ask for help.. or sell the horse and take lessons on horse handling and confidence building riding.
Here is my reasoning.
I wish I could take my horse to shows, playdays, and clinics, but I have one problem; my horse acts up, won't focus, and gets very edgy, jittery, and tense in indoor arenas. He is so intent on looking around and spooking at the slightest noise and looking at the bleachers, equipment and setup out of the ring, that I can't even get his focus on me. He almost ignores me.
Okay this right there worries me! He sounds completely untrained and he's not respecting you at all. This is an absolute recipe for a complete and utter disaster. He needs more training. By a trainer.
And you need to either get some training yourself on how to work with a horse (not just ride) or you need to get a different horse. You are both going to end up seriously hurt!
Usually when we get there, we'll walk in and get to warming up by just walking around the rail for about 5 minutes. This is when he looses focus. right away, he get's tense, becames alert, his head goes up, and while we're walking around, he thinks he sees something, and wheels away and either trots or lopes away from whatever spooked him, whether it be a trashcan, a barncat, or a shiney doorknob. I can't keep him from running back to the entrance and of the arena.
Again... lack of respect. He's psyching himself out.. why? There's no leader for him to follow. You're supposed to be his leader. Since he's obviously got your number.. he knows he can get out of anything by pretending things are just.. terrifying. And again... recipe for disaster.
We'll be walking around the rail, I keep as calm as I can, (but I have to keep on my toes in case he decides to try to turn and run) and he'll stop for a quick second, look around, and try to turn back (Sometimes he sees something and spooks and shies away from it, and tries to run away before I get a hold of him). He'll do maybe a quarter turn, and I can get a hold of him, and try to get him to move forward again, but with head held high, snorting and acting nervous, he usually won't budge, and tries to turn back many times while I attempt to make him go where I want to. usually he is the least tense, if at all, down at this end.
Look.. if you let him have an opening like that, any horse will try and be an idiot. Horses need focus. Focus comes with asking them to do something, and then another thing.. and another thing. Like oh hey! Let's change directions.. let's do a leg yield.. let's move into a trot. Let's stop and back up. Let's stand still then move off into a large figure eight.. etc.
It should not even progress to "and he'll stop for a quick second" No! You push him on. YOU are in charge.. the horse follows YOUR cues.
This is where the opening is, and all the parents and trainers are over here on the rail by the gate talking. Beyond the opening, there is a parking lot. On the opposite end it is the worst. He often tries to turn around and run back to the other end of the arena. In the back half of the arena he spooks often, and is always tense.
Of course he's more tense.. he's a metal building and there is probably echo. But it doesn't matter, he is trained to deal with it. If you can't train him or pay for a trainer.. get another horse. This will get you killed one day.
I was at a playday a few weeks ago, and we were waiting in the barn on the side of the ring for our names to be called for the next event (which I believe was poles). He was standing calmly, and almost half asleep, Then our names were called, I knew we were gonna have to take it slow, so I walked in there as calmly as I could for his sake, yet I was holding my reins tight in case I needed to. he walked calmly for a few steps (not even to the poles yet), so I kicked him into a trot, and about halfway up the poles, he out of the blue tried to turn back, and he got himself almost all the way turned around before I reached down and pulled him in. when we got to the first pole, he trotted around it, then stopped and tried to run(we were now headed towards the 'safe end' of the arena), but I stopped him, and tried to make him back up hoping it would make him think about me and not his surroundings, but he completly ignored me, and kept his head up and alert, and wouldn't move. We went through the rest of the pattern with most of the same patterns, stopping and trying to turn back.
You don't kick a horse into a trot. I'd run away if I was your horse too. It sounds like he just doesn't get a chance and he doesn't sound trained. You both need coaching.. separately. Then together. You ride with your body, not your hands. You ask nicely, then up the pressure until you get what you want. When you get what you want, the pressure STOPS. Next time, you ask softly and until they give you what you want, up the pressure.
Simple pressure release. No pulling.. no kicking.
Please help me, I am at the end of my nerves, and I have had to quit going to the show barn because of this. It is very flustering and embarrassing to me, and he never behaves in there.
You need to find a trainer for him and for you. Or you need to get another horse. He sounds like quite a mess, but judging from your post you do as well.
Please, for the sake of your safety and his. Get a trainer or sell him.