Hello, Eckhart Tolle describes the pain body as the emotional aspect of the ego. I recommend reading or rereading the chapters on the pain body in A New Earth. Eckhart and his wife, Kim Eng, also have many videos and teachings about it. The pain body can trip us up even more than the ego, because the emotions are involved, specifically old unexpressed emotions.
I’ve named my pain body Old SUE = Old Stuck Unworthy Energy. she loves to try to pull me down and get me to wallow in self pity. I think I’ve posted a pic of her before, but here she is again:

She’s very heavy and loves to wallow in the muck! 😅 I did find it really helpful to look her in the face–lol!
Anyone else want to talk about their pain body?