Strangely enough, my observed progression of intense physical pain
is slightly different:
1. Impact. In the case onhand, we're talking about hitting a rock with the front wheel of a bicycle and driving a spoke well into the calf.
Step one is usually not even observed, as I found myself on the ground with about three frames in mind - Having looked at the sky I didn't see the rock, but got a good glimpse of the grass encroaching via the handlebar.
2. On the ground, in shock, what the hell happened. Looking around, I see my bike obviously out of shape, a metal rod going into my windpants (which is removed with one pull) but everything else seems alright. Robotically I get up - no pain, but my body temperature has dropped quite a few degrees; I feel sterile.
3. Two minutes down the road, sitting down at my house the pain sets in. Realizing that there is no longer a need to stay coherent and free of pain, my mind enlightens me as to what the problem is.
From this point on we follow Starrynight's observations rather close, with the pain of having an injured muscle and the process of disinfecting such a deep wound.
I still think it's comforting to know that we can mentally control pain, therefore that it is used by our body to help us... not inflicted by the environment.