I take prescription drugs for pain. The drug(s) are addictive if improperly used.

Also, I will be carrying a 30 day supply as I will traveling to Thailand after visiting China. The amount will be more than my stay in China. Will they take the additional drugs? Will they take the entire set of drugs even with a doctor's note and the prescription bottle with my name on the label? Should I declare the pills and travel in the red line in lieu of the green line?