Possible flaoters in vision. Help.

I have noticing strange  symptoms from last 6 months. First it started like suddenly unable to read text on screen, somekind of pulsating at corner of both eyes near nose and  after few minutes headache was started. Headache was not observed every time when I was suddenly unable  to read text.Went to eye doctor,he used light and drops to test eye and confirmed no issues.Went General Doctor,gave some tension headache tab and B12 tablets.After using those,above symptoms gone.But high number of black threads observed. Those only can see in bright light.Went to eye doctor again in another hospital, they used light test (white & blue light) and drops they confirmed that no issues(no retinal tear or hole).Some times I observed eye light pulses when closing eyes with hand especially after usage of phone.Now I am seeing fast moving dots if seeing white bright wall. Also observing some kind small pulsating vision (think ripple effect)while walking on road under sunny day. worried.please help.