Originally Posted by Eolith
Just keep in mind that a stall is a pretty confined space and you need to be very aware of his position in relation to you at all times, as well as aware of just how angry/upset he is. If he just acts up worse, I'd definitely get out of his way and ask someone with more experience to work with him.
Totally agree with everything Eolith said. If you are not comfortable working with this horse in the confined area of his stall, if there is a paddock connected to it, you may consider opening the door, and pushing him out into it. It would give you more space.
I have known several horses, that lived in stall all of the time, that when you come into their space act like this. They would not pursue the issue, and usually after I patted them, they would relax and let me do whatever it was that I was in there to do.
I've only ever known one horse that was a true pest, and the people that I worked for at the time did not want me correcting him, only they could. Well, that didn't help me when he was trying to pin me in the stall. When they started letting me work the horses for their daily exercises, I put an end to that horse's BS. I ran his little halter horse legs off. After that, he didn't bother me anymore. They never put two and two together on what happened either. They just noticed that he was better behaved. That horse also changed a lot after they had him broke to ride, and was ridden daily instead of only worked for 15 minutes a day and locked in that stall for the rest of the time. I felt so sorry for all of those halter horses, and I ran into more stable vices at that barn, then I have at any other one.