I would agree it does seem odd. Although, 'fire' is used figuratively elsewhere in scripture, even when not in a parable, so it might be used that way here?Whether literal or figurative, I do not know, though I do find it rather odd that the explanation of a parable would also be figurative. (Paidion)
eg.
Rom 12:20 Therefore if your enemy hungers, feed him. If he thirsts, give him drink. For in so doing you shall heap coals of fire on his head.
1Pe 1:7 so that the trial of your faith (being much more precious than that of gold that perishes, but being proven through fire) might be found to praise and honor and glory at the revelation of Jesus Christ,
Hi, I believe that too, just not sure if the pain will be physical, or more like mental anguish (or both).If the parable is figurative one thing for sure it has a literal meaning.
I believe the literal meaning is that those who offend Christ will suffer in pain.(PAULESPINO)