You are really scared of something so you are trying to get away from it. Do you have bad memories that are trying to catch up with you, and you just want them to stay gone? You are trying to get away from something which you believe could cause you mental or spiritual harm.
In many dreams, to see a bug running after you or a fly buzzing around your head is meant to signify a problem. If you are to see a bull running around and chasing you, this means that you are running away from your problems. Only, in this case this is not meant to signify a lot of problems like a swarm of bugs might, but one, really particularly aggressive problem that is really bothering you lately. If you are participating in the running of the bulls in your dreams it means that you are running away from a lot of big problems that you cannot seem to reconcile. This is a big important deal and something which you should not disregard or leave in the dust. You need to consider how dangerous and threatening your problems are and whether or not it would be a good idea to run away from them. Sometimes you can actually get away from the things that are chasing you and find a little room to breathe in the world. However, other times when you are confronted with these problems you might need to stand and face them.
To gauge whether it would be a good idea for you to keep running or not would be to see whether or not you can see the exit. Can you see the exit within your grasp and do you think that you could make it if you try really hard? In this case it would mean that you successfully outran your problems. If you cannot see the exit, then it means that the bulls will eventually overtake you because they are faster than you. They will gore you if you make one false move, so you need to face it rather than being trampled and see what you can do to defend yourself.
To dream that you are a bull means that you are quick to get angry about things and you are really short tempered in life. You need to be able to relax on some occasions and realize what it is important to be angry about and what will be detrimental to you. You do not need to get over exaggerated about things in general because anger solves nothing in so many cases. Simply try to be a calmer person and things will work out better for you in general.