This is normal that when you look at the computer for too long a time without a good rest for your eyes. First of all, it is because that you do not allow your eyes to get adequate rest, so the muscles of the eyes have always been at a condition of tension and feel aching. Besides, the blood vessels, owing to your continuous working with computer, have got congestion and make your eyes feel burn and swelling pain. Secondly, your eyes have always been looking at the computer which will lead to dry eyes. The radiation of the computer screen and the radiator of the computer will make your eyes accelerate the water evaporation of your eyes, both inside the eyes and the skin around the eyes. Therefore, your eyes feel burn when you look at the computer. To reduce, you should pay attention to have a rest when you have read or worked for about an hour or half, use some eye drops and do some eye exercises. Eat more foods that are rich in vitamin E which is good for your eyes.