You could be experiencing the symptoms of a posterior vitreous detachment (PVD) which are similar to a RD but is usually benign and is a very common, normal occurrence. Usually this would not happen at your age, but since you had eye trauma, this could cause it to happen earlier in your case. If you have had thorough exams and they say your retina is fine, I would say PVD is likely what you are experiencing. Unfortunately in a young person like you, the PVD is probably a long way from completion and you may be dealing with the flashes for a long time to come. The floaters won't really ever go away, but you will get used to them and tune them out.
If you experience a sudden "burst" of new, tiny floaters like soot, that is different, and could be a RD. The floaters you describe are probably nothing to worry about, just annoying.
Well thank you, doctors keep telling me that my retina is fine and as you said it could be PVD, but in the last week i felt like those floaters are doubled and became more visible to me, i couldn't walk or read a book without seeing them, and I'm afraid that in the future, i may GET MORE and MORE floaters !! Is there anything that i could do to stop the floaters from coming in the next few YEARS? and to only deal with the present floaters ?