I am an EMT, not a paramedic, which is a higher certification. My best guess is that CPR does not hurt because the patient is technically dead when you do it - no heartbeat. Maybe the brain cells linger on some; supposedly hearing is the last sense to go, and I worry more about the casual conversations the patient might hear, as if he doesn’t matter, rather than any pain.
Paramedics (and EMTS, doctors, nurses) are not eager to do CPR on the old old or terminally ill. If the patient fits those categories I always ask, is there a DNR? I remember one elderly woman who had metastasized pancreatic cancer and was on hospice care but there was no DNR because the family didn’t want one. So the cop and I hauled her off the bed to the floor, bared her chest in front of her teenaged grandson, broke her ribs, brought up stomach contents, and I kept thinking, at least she’s gone already. If it was my mother, I would have held her, and told her I loved her.
So far my only CPR save, as in the patient came home from the hospital (return of pulse is common, return home much less so) was when I saved a resident of a group home from CPR. He was conscious when I got there, so I told the staff they could stop compressions...oy.
When my daughter was getting certified an EMT is the lower of the two. She will be pissed she did two more years of training and gets paid more for running the ALS ambulance.
If a person still has enough of a neurological system that they can be resuscitated, there is no reason to believe that the pain cannot be transmitted and registered by the brain. That is why when you wake up from surgery, you feel so beat. The pain is still transmitted, you just can't do anything about it.