I have found it uncomfortable to look upward towards my spiritual eye while also concentrating on the Hong-Sau breath. Today I become confused as everything I had read had advised to look upward: Until I found This:
Should one concentrate on the breath and also at the point between the eyebrows
Not until the attention focuses itself naturally on the flow of breath at the beginning of the nose. To do so otherwise would constitute a division of concentration which would be self-defeating
—Suzann, United States
You should lift your gaze only slightly above the horizon. Perhaps you are turning your eyes up at a sharp angle, which would be both difficult and uncomfortable. In any case, do not try to see something in the direction you are looking, as that will divide your attention, which should be completely on the breath. Concentrate on your breath wherever you can feel it most easily. Gradually you will feel it higher and higher in the nose, until you feel it at a place toward which your gaze is turned.
Here is an approach that Swami Kriyananda suggested and you might find helpful: feel as though your eyeballs exist only in the upper half of their sockets. In this approach, there the gaze will turn slightly upward by itself. Try it.
I hope this will help.
Blessings on your practice,