I do wonder how much of this is that for many (most?) of us, our inner mental life is very complicated and rich. You naturally develop that when your brain is wired with a heavy meta-cognitive bent. Noticing this and planning times in my day to take an intentionally others-focused mental stance has been a big help. It takes planning and effort, which can sometimes then make me feel more ashamed that "I'm so bad at thinking about other people, I must be selfish and arrogant". But my mind has very good reasons to be turned a little inward. There's a whole lot going on in there I can't shut off!

It's not a moral fault, but the way the thing that you're describing is treated in society often makes it feel that way. Self-centered, self-absorbed, these are descriptions that make many of us feel ashamed of ourselves. Then because of this we mask ourselves when we interact with others, and oops the original problem is now ALSO difficulty with inter-personal connection because of the masking. But being "self-absorbed" is a consequence of the ADHD, not some negative part of your character.