This totally describes me. The line I quoted resonates because sometimes the idea of a boring task is actually frightening to me, in the way you described. Like I get a really sick feeling about it and will do almost anything to avoid it. On the other hand I feel like I have so much going on in my head, and so much I could produce if I could only channel it properly. The TV is most definitely always on. My lack of focus and procrastination has definitely held me back in my career.
One thing I'm wary of is medicalising what might just laziness. How do I know it's not a version of "special snowflake syndrome"? Is my own inattentiveness (and inability to get over it) really so much worse than what a "normal" person experiences?
To give a parallel, I heard a podcast where Ramit Sethi was talking about "introvert porn", where he's saying there is all this stuff online about how hard life is for introverts, how extroverts don't get it, basically making people feel good about being an introvert and telling them that it's an integral part of who they are rather than something they can change. And he's saying that this is a dangerous and self-defeating trap to get into because people don't realise that social skills can be learned. All these "introverts" are just falling back onto an excuse to avoid confronting the thing that's holding them back.
If I start blaming all my problems on ADHD am I just falling into a similar trap? After all, not everyone can be successful. Maybe I'm just not successful because I'm not that good at anything, not because of a medical condition.
Possibly relevant: I am in the UK where ADHD seems to be a lot less recognised than in the USA. People here are often critical of the idea of medicating ADHD in kids (which is relatively unusual here afaik). I don't know how a British GP would react to someone asking for an adult ADHD diagnosis - I imagine it wouldn't be taken very seriously.