Why am i seeing flashes?

when i playing anything or just sitting around like the lazy kid i am i see white glows or flashes off to the right side of my eyes and it always coming from my bed room i go in there and nothings making that light i Stand there for a good 30 min and nothing i go back to sitting and it happens Again ive bin having this go on since i was 8 years old and wondering why who or wats causing this