Daily eye flashes. What is that?

From past three years I am seeing flashes of light like a white shinny light moving in the edges of vision multiple times a day daily for few seconds. I see them in one eye at time but I see them in both eyes when I sneeze. Mostly flashes happen in both eyes but in different times.during sneeze they move in circular motion but only in the edges of vision my retina brain mri and bp whenever checked came out normal.it started mid pregnancy.but suddenly one day when I am so stressed I saw a colorful zigzag type pattern in the side upper vision .( It didn't move).I panicked and rest and it went away after minutes.i never had headache after any flashes.my blood test are mostly normal.mostly the white orb type flashes that move happen for seconds but that typethe shinny colorful thing lasted for minutes at same place.what is that??please help.iz my flashes that I am getting every day correlate with that flash I saw that day zigzag type