I have a hard time putting myself into someone else's shoes when it comes to physical feelings. When I'm full, I can't imagine being hungry. When I'm hot, I can't imagine feeling cold. When I'm feeling okay, I have to force myself to register intellectually that because the other person has a headache they might not want to do XYZ.
This empathy failure extends to relating to future me. I have a hard time picking out clothes for tomorrow when the temperature's going to drop. And after 20+ years, I am still full of disbelief when my husband says we need to pack sandwiches for a hike that extends past lunchtime. I literally cannot imagine being hungry.
But I just really feel guilty when one of my kids hurts her knee and I have to...pretend to empathize because I'm not feeling it. And sort of intellectually consider what that means and how I should be reacting.
Luckily, this isn't the case with non-physical issues. I mean, I'm fairly good at relating to people's complex feelings of all kinds, and it all seems to come naturally.