Plants are not cognizant. When we cut a leaf, we assume that the plant is suffering. But that's our own anthropomorphism about what's going on.

The idea that damage has to be pain is mistaken. We feel pain because we have specific types of receptors called nociceptors which are programmed to respond to pain, not to touch. People can have genetic malfunctions where they feel pressure but never feel pain because they don't have pain receptors.