What @stevecando54 said.

My cancer metastasised to my middle spine and damaged my spinal cord severely, so I have phantom nerve pain all over from the ribs down, and conversely don't always feel pain that I should. It took me time to trust that pains that come and go or move around aren't new metastases (a sustained PSA < 0.01 helps my confidence a lot as well).

I write down anything I'm really worried about when I notice it, then erase it if it's gone away again in a week or two. Very little of it makes it to my quarterly oncology appointments, and of the ones that have, medical imaging has confirmed they come from other causes: recurring bladder and rectal pain from radiation damage, and recurring pain between my spine and right shoulder blade from a knot of fat, muscle, and scar tissue left over from my emergency spinal surgery.