I always wondered that. Did getting stunned actually cause you any physical pain, or was it just a loss of physical control of oneself?
I've seen quite a people getting Tased on TV on those various "caught on camera" shows, and it seems to cause both physical pain and a loss of physical control. In comparison, we've seen phasers set on stun either make a person very groggy and docile (like Professor Crater was in TOS' "Man Trap") or knocked completely out cold.