but plants are alive too and they can actually feel pain
As someone who actually took college level biology, I refute your claim. They don't have nerve cells. They have http://en.wikipedia.org/wiki/Plant_hormones and that's about it.
No nerve cells, no brain, no pain receptors. It's like asking "oh, gee, do you think this
E. coli will feel pain if I slap it?"
Can plants react to damaged parts of themselves? Yeah, of course, they have an immune system. Can some react to touch? Uh-huh, that's the plant hormones thing again. Do they actually "feel" anything? No, they don't have a central nervous system.