Sri Aurobindo
Letters of Sri Aurobindo
03. The Triple Transformation: Psychic – Spiritual – Supramental
The good condition of openness with the Force descending and the constant remembrance – or whatever other form the condition takes – is the beginning of the true consciousness and its duration is always short at the beginning because the ordinary consciousness is not accustomed to it, but to something else. But it always increases in duration and power until it is able to maintain itself even when the outer consciousness is occupied with other things. At first it remains there as something behind which emerges as soon as the outer preoccupation ends; afterwards it remains behind, but as something just felt, and in a later stage it is always there, so that there are two consciousnesses, the inner consciousness always connected with the Mother and full of her 
working or her presence or both and the surface consciousness occupied with outer things. Finally, even the surface consciousness begins to feel the direct connection in action itself. One need not mind if there are intervals when the true condition is not there. It does not prove that you are unfit; it is only a period in which what is not yet changed comes up to be worked upon and prepared for change. When the inner consciousness is well established, then these periods take place only in the surface consciousness and are no longer troublesome as before.
P.S. Probably the difficulty you feel is in the externalising mind the centre of which is in the throat. When there is no resistance there, the Force comes down to the heart level and below.