As someone with a herniated lower disc that presses up against my spine (and is doing so right now), it radiates to the actual receptors.

But those receptors can be anywhere and everywhere. I feel pain in different locations depending on "how" my disc is currently herniated, inflammation in the area affects this as well.

Right now my actual butt is in a lot of pain, but it can radiate all the way down to my toes sometimes. This is all from the disc pressing against the spinal cord in different micro locations, nothing is actually touching the pain receptors in my bum (other than my clothes, I guess).