I am starting to lose count of the number of headache and migraine cases that are coming in as a result of this situation and that is why I wanted to discus it today.
Most of the time, if people have two screens, they set them up one slightly on the left at an angle and the other slightly to the right. The problem is this means your neck is turned either left or right all day long and this creates headaches because it is difficult for your body to sustain constant rotation for a long period of time.
Solution: The best setup would be to have your primary screen right in front of you, and a second smaller screen above or below this to avoid the effect of sustained rotation. Of, if this is not possible, have your primary screen in front of you and the screen you use the least on one side or the other. In this scenario, you will have to swap this secondary screen from left to right on a week to week basis to avoid creating an adverse patter in your neck.
Don't underestimate this. I had a patient present recently who had been hospitalized with a three week worsening headache and after I told this person to move her screen, her headache resolved and there was virtually no treatment involved.