Watching films of Miles Davis performing in the 50's and 60's I noticed that whenever his solo was done he would take his index finger and press it beneath his right ear. Sometimes he would also shake his head as if it were painful to do so. I'm not sure if he did this later in his career or not. He acted very differently on stage in the 70's and later.
Is the pressure from blowing the horn forcing air into someplace it shouldn't? Why only his right ear? Is this common among trumpet players?
Here are a few stills of him doing this: