I was at ease, but he hath broken me asunder: he hath also taken me by my neck, and shaken me to pieces, and set me up for his mark.
I was at ease - in past times, (Job 1:1-22.)
By my neck - as an animal doth its prey (so Job 10:16).
Shaken - violently: in contrast to his former "ease" (Psalms 102:10, "Thou hast lifted me up and cast me down"). Set me up (again).
Mark - (Job 7:20; Lamentations 3:12). God lets me always recover strength, so as to torment me ceaselessly.