Why do I feel headache sometimes during nasal irrigation?

The most common causes are:

Water temperature: please use warm water. The initial water flowed out from the device is usually cold, so allow the device to run for a few second until warm water coming out.
Salt concentration: too high or too low salt concentration may irritate your nasal cavity, especially when no salt is added in the water, or salt is not well dissolved, or added salt is not enough.
Pressure: please try a lower water pressure.
Water comes out from my nose 30 ~ 60 minutes after irrigation

Many people, even doctors, question if nasal irrigator can really rinse into the paranasal sinuses (it is true that many traditional nasal irrigator cannot completely rinse into the paranasal sinuses). This question is a good evidence to prove that this pulsatile nasal irrigator can effectively rinse into your paranasal sinuses.

Some factors that prevent water from freely leaving your paranasal sinuses are dysfunctional muco-ciliary movement in your paranasal sinuses, and the swelling at the entrance of your paranasal sinuses and nasal cavity. Hence, the remaining water comes out from your nose only when your head is bent downwards to a certain degree. To resolve this, you can bend down your head and turn right or left to facilitate draining of the left over water in your paranasal sinuses. Regular pulsatile nasal irrigation can help you to quickly recover your sinus muco-ciliary movement function and bring down the swelling.