I have a question about a headache?

[iluvuglydolls]

I am a 14 year old girl...I have been having headaches on the left side of my head for the past few weeks. They are always in the same place. Could using the computer frequently cause this or could it be something else. I feel fine...I can walk, talk, and my pupils dilate when they're exposed to light. Should I be worried about this headache or is it nothing. Thanks!