Board Thread:Questions and Answers/@comment-27322187-20160118142216/@comment-26653902-20160119231616

Actually, in the manga, Touka also looked like she was in pain when Ayato was eating her kagune so in her case at least, it seems she could feel pain.

Considering how neural impulses are required for any part of the body to do anything, I'm pretty sure there are at least nerves in kagune, and since all nerves will transmit pain when damaged regardless if they are nociceptors (sensory neurons for noxious stimuli including pain), logically ghouls would feel it to some degree on the occasions their kagune are damaged.