The first important thing is to get your eyesight tested and start with glasses if needed. The condition you are suffering is known as Digital eye strain or Computer vision syndrome. Follow tips like the 20-20-20 rule while using digital devices, adjust screen brightness according to surrounding lights, and keep the screen 10 degrees below eye level. Additionally some medications can help in relieving eye strain.
Next Steps
You can consult with an ophthalmologist for the right medications and additional tips.
Health Tips
You can follow my article on Digital eye strain available online