What could my eye strain and blurriness be from?

Visual acuity: It could be from many things, but the most likely is from astigmatism or simply a need for vision correction. You should have your eyes evaluated.

Eye Strain: Eye strain can come from excessive reading, computer use, or any visual task. When doing close work such as the computer, take frequent breaks where you look away from the screen or periodically close your eyes. Varying the distance to the screen can help. Avoid getting too close to the screen. You may need an eye exam to see if glasses are needed. Eye dryness can worsen symptoms as well.