is "stop asking why" also a possible answer?
No because "stop" is dừng/ngừng/ngưng.
Đừng hỏi em vì sao, tình yêu ta úa màu
This being a "phrases" sections, is "đừng" always "do not", or is it ujique to this phrase? If it is regularly used, is there a defined set of verbs that we will not negate with không?