Well, yes, it is normal to have sore eyes, when you are tired. Generally speaking, when your eyes are tired, it will just increase the eye pain. And in that way, it can just lead to a lot of eye problems, such as sore eyes, even dry eyes. And when you suffer sore eyes, your eyes will feel itchy, dry, and painful and discomfort. So you should try some ways to cure it. For example, you can make an eye pack made from chilled cucumber slices. Just put those under your eyes, and it may be very beneficial. Of course, you should have a good rest and then, it will be fine.
Well, it seems that there is something wrong with your eyes. You should know that ,generally speaking, our eyes would not be sore even if we have gone through a whole day's work. You should know that sometimes improper use of our eyes could lead to sore eyes, such as long time exposure to computers, consistent use of eyes and some other problems. What you should do is to get some eye drops , and if the situation remains bad, you need to see a doctor.
In my opinion, you must stay in the computer for a long time, because the radiation of computer can do harm to your eye health. Also, your working environment is not so good, with insufficient light, which can lead to eyes sore. Of course, you can restore with suitable ways. For example, you can rest for several seconds to relax eyes, and ask for a lighter working environment.