Yes, eye pain can cause headache, because the nerve between your eyes and brain is connected. For example, frequent computer use can make your eyes feel painful can then contribute to headache. When you feel headache for your eye pain, you need to lie down and have some rest. And you can consult an ophthalmologist to see if there is a problem with your eyes.
No, eye pain won't cause headache. From your description, you feel headache because of your get tired after work in a while afternoon. And you get eye pain is also caused by eye strain and tired. In common, we are suggested to take a break every one hours when we work or reading something. And it seems you were work hard and didn't take care of your eyes. So, it is normal for you to get eye pain and headache. Just take a rest and go to bed early. I believe you will recover tomorrow.
Yes, the eye pain will cause headache because of the interlinked eyes nerves. You could use the warm compress to make your eyes feel comfortable. At the same time, you could also use the eyes drops with anti-inflammation to comfort your eyes. You'd better check the main problems for your painful eyes. Then you will clam your headache and make you feel comfortable and healthy.