Physical sensations are not reliable indicators of anything at all!
We should evaluate our pranayama by the effect on our psyche.
Pranayama should help us relax, especially psychologically.
Furthermore, pranayama should strengthen our ability to self-observe.
In short, pranayama should be helping our consciousness. Are we becoming more aware? More patient? More chaste? More serene? Less irritable, demanding, dissatisfied?
That cannot be measured by physical sensations.
“Nothing is easier than self-deceit. For what each man wishes, that he also believes.” —Demosthenes
"Do not worry; cultivate the habit of being happy." —Samael Aun Weor