Some ppl detect flicker from artif. lighting. but i sense flicker looking at natural daylight. if eyecheck ok +no other sx, could it be brain problem?

Flickering: Visual cortex has a particular way of processing vertical & horizontal lines. Some migraineurs are bothered by strobe effects: Driving past telephone poles, shadows from spinning ceiling fans, sun shining through venetian blinds, etc. I wouldn't call your thing a "problem" unless it's so distracting it interferes with your life, eh?