I can't say for sure if the seizures are painful but I think, for our dog, they were.

The type she had made her muscles go rigid.

Just holding muscles that tight for a few minutes would surely be painful.

Often people don't recall the experience of the seizure, only that they had one. I don't know if it's the same for a dog.

A friend of mine who has epilepsy told me that he has an insanely painful headache after he has a seizure.