You may be experiencing that sense of multiple thoughts because the thoughts change so quickly. The best description I've heard is that its like jumping from A-G without anything in between. Tell me if this sounds similar to what you're experiencing. While trying to perform a task everything else in my life bombards me. It may not even be relevant stuff. But I'll be thinking, oh I need to do my laundry, last week when I had that conversation with so and so did they mean this or that, I'm hungry, I need to buy shampoo, oh god why did I say that, I really wanna travel, I need to do laundry. I've also thought of my thoughts as a web, and not linear as how most of our society functions. I think A,F,G,L,Z, and then back to A. And then it repeats. Each idea takes a turn, then a new idea, then back to an old idea and build on it more. Hyperactivity can refer to how quickly the brain processes, not just physical activity. Medication has helped me with this, but also I think being physically active, almost using up energy helps too. Meditation is a good method of really harnessing the mind too.