Photo Source: Picryl Pain - what is pain? If you can’t see it, does it exist? Invisible pain like mental illness, or some debilitating trauma for which you are its only witness, is something personal. We each experience it as an individual torment, never shared. I see it as a haunting presence: something that waits in the shadows; that arrives uninvited at dawn or in the middle of conversation, reminding me of my mortality. But how do you describe it? How do you measure or compare it?   I...