One way that acupuncture and acupressure work for reducing migraines and headaches is by treating pain along specific acupuncture channels (also called meridians). Different meridians go to different parts of the head, and you have to choose the correct one to be effective. Click here to read some background on acupuncture channels and points.
Headache locations and channels
The choosing the correct channel depends upon choosing the proper channel.
Frontal Headaches- Stomach and Large Intestine Channel points are the most effective. This is because the stomach and large intestine channel covers the forehead and sinuses. LI 4 and ST 36 are both good points for this area.
One sided or Temple Headaches- choose the Gall Bladder and San Jiao channel. This area is covered by these channels. GB 34 and GB 31 are discussed in my previous post, Acupressure for a Kid with a Headache.
Back of the head or occipital headaches are treated best by Urinary Bladder channel. Points at the end of the channel, such as UB 60, UB 65, or UB 67 are all effective. These points can be found at Acupuncture.com.
Headaches that are located behind the eyes are generally from Kidney channel imbalances. These headaches are often difficult to treat with acupressure. Acupuncture therapy can help to boost the kidney qi to stop the chronic headaches. One of the points that is often effective is Kidney 3.