The Characteristic of Dukkha - The five khandhas of clinging are dukkha

Questioner: I have studied the text the monks chant in the morning, about the khandhas of clinging, upadana khandhas. There is clinging to the five khandhas and this is dukkha. What does this mean?
Sujin: The five khandhas of clinging are certainly dukkha. So long as there is ignorance of the true nature of the dhammas that appear, there is bound to be happiness and sorrow. The arising of happiness and sorrow is a kind of dukkha, because at such moments there is no calm, no freedom from defilements. People do not know the difference between kusala citta and akusala citta when panna does not arise. We all enjoy having lobha. There is no end to the enjoyment of lobha, unless panna discerns the difference between the moment of kusala, when there is nonattachment, and the moment of lobha, when there is pleasure, amusement, desire, enjoyment or clinging. 
When panna does not arise, we enjoy defilements, we like to have lobha; it never is enough, no matter whether we experience an object through the eyes, the ears, the nose, the tongue, the bodysense or the mind-door. Generally people do not know that such moments are dukkha, that they are  harmful and dangerous. Thus, the five khandhas of clinging are dukkha.
Questioner: If we are heedful when objects are impinging, for example, when visible object contacts the eye or sound contacts the ear, there will be neither happiness nor sorrow.
Sujin: There is not “somebody” or a “self” who could be heedful or force the arising of sati. When sati arises we can know the difference between the moment with sati and the moment without sati.
Questioner: The five khandhas of the ordinary person must be the same as those of the arahat, but the khandhas of the ordinary person are still objects of clinging and this causes the arising of dukkha. When we gradually learn to be heedful when sense objects such as visible object or sound are impinging on the relevant doorways, do we develop satipatthana in the right way?
Sujin: One should remember that all dhammas are anatta, non-self, so that sati can be developed in the right way. One should know when there is sati and when there is no sati. When one has a concept of self who is heedful, satipatthana is not developed.