Sometimes my left eye gets blurry and sometimes my right eye can that be a brain tumor? when im on the computer also when looking at the sun

I really doubt it...: The key word you used was "sometimes". CNS tumors are generally characterized by the onset and progressive worsening of symptoms, and symptoms depend upon tumor location, infiltration, and the impact on intracranial pressure. What you describe sounds more like eye strain. Give yourself a break from the screens/sun. If blurry vision persists, may need corrective lenses. A checkup may mitigate fears.

Two things: First, don't look at the sun-- it's a bad idea. Second, it is common for people to blink less when they are staring at a screen. The resultant dry eye can cause temporary blurred vision. You might try to give yourself a drop of an artificial tear when this happens. If it clears up, you've got your answer.