Not buying it. There is simply no need and, realistically, no way to replicate the feeling of pain in a non-living organism. The mere fact that David even resembles a human at all is to make other humans feel more comfortable around him. This is a fact that even he admitted. Of course, when something looks human and can appear to feel based on facial expressions, there is no doubt that it can create confusion. Shaw could've just a easily kicked his head around like a soccer ball and it would've made no difference.