As from your history that you are using computer for long time. This is a common condition called as Computer vision syndrome
. All these symptoms are because of dryness of eyes.
The treatment of the condition is by taking proper precautions while using computers for long time. The precautions required are
1. Taking break from your work at frequent intervals like atleast 2 minutes break after working for every one hour.
2. Seating adjustment such that your eyes level above the monitor of the computer.
3. Not to use air conditioner or fan with flow of air directly into the air which may aggravate dryness.
The treatment of the condition is by artificial tear eye drops. If teh symptoms persist even after taking these precautions, I advice you to consult your eye doctor for evaluation and treatment.