Chest and head rising higher are sensations of the subtle body, it means that the mind and heart consciousness (thinking mental and emotional) are rising to meet the spiritual consciousness plane above the head.

This opening of the chest into the void (not really the void, but the infinite Akasha of the Chit universal and illimitable) is always the sign of an opening of the emotional being into the wideness of the Universal Divine. The image of the Akasha is often seen by sadhaks in Dhyana. When the consciousness is liberated, whether in the mind or other part, there is always this sense of the wide infinite emptiness. From the top of the head to the throat is the mental plane of the being a similar opening and emptiness or wideness here is the sign of the mind being freed into the Universal. From the throat to the stomach is the higher vital or emotional region. Below is the lower vital plane.

The Knowledge comes from above like the light and peace and everything else. As the consciousness progresses, it comes from a higher and higher level. First it is the higher illumined mind that predominates, then the intuitive, next the overmind, lastly the supermind; but the whole consciousness has to be sufficiently transformed before the supramental Knowledge can begin to come.

Oceans of being met his voyaging soul
Calling to infinite discovery;
Timeless domains of joy and absolute power
Stretched out surrounded by the eternal hush;
The ways that lead to endless happiness
Ran like dream-smiles through meditating vasts:
Disclosed stood up in a gold moment's blaze
White sun-steppes in the pathless Infinite.