Your brain randomly generates your memories distortedly. If you think or worry about something for extremely long periods of time, you may dream about it. If your anxiety level is high, you'll dream about your fears a lot. But you cannot decide specifically what you want to dream or if you can dream at all.
your confusing dreams with thoughts you can't control dreams that's all your subconcious and feelings you don't realize you feel, but thoughts are in your control and you can think in your sleep your sleeping light enough does that make sense