Close your eyes, focus your entire concentration on the nearest area that is not in pain, especially focusing on any parts of your head that are not in pain. Experience this sensation of in the fullest detail you can. Imagine that the other part no longer exists, only the focused parts are real. Now gradually imagine the area of these parts expanding, slowly and painlessly, until your entire head's surface is covered by the sensation of normalcy. If done properly, you will not even notice a change, but your headache will be gone. If it worked, congratulations, you have just discovered the art of healing meditation.
I would not recommend this for any serious ailment or as a substitute for medical treatement, but for life's small discomforts, it can work wonders. For instance, since discovering this process, I have only had to suffer headaches from sleep deprivation, when I lacked the necessary concentration for this sort of thing, or severe sinus infections, where the pain would just start right back up because of continual causation. In these years, however, I also have not refined it much beyond this.
This technique, particularly, is one I discovered towards the beginning of junior high school. At the time, I was suffering from an incurable ailment called Chronic Fatigue Syndrome (later to be known as Chronic Fatigue ImmunoDeficiency Syndrome), and someone I had recently met with Fibromyalgia (and possibly Multiple Sclerosis -- my memory is a bit fuzzy on this point) told me about the work she had been doing with biofeedback. Biofeedback is something she described as basically "lying to yourself until your body believes it". The upside was that it had had a fair amount of success in treating some otherwise intractable ailments like ours. The downside was that, success and failure alike, biofeedback patients had a pretty high chance of going on to become pathological liars, perhaps indicating that the work was better cut out for hypnotists or placebo pills. And though the Chronic Fatigue eventually went away in my case, it was not because of biofeedback or healing meditation or any such a thing. See, in my case, it seems to have been entirely caused by severe mold allergies, and my family eventually moved out of the water-damaged apartment we were in.