I cry everyday,because my mind suddenly getting the flashback of a traumatic event just happened. is it normal?

No: This is obviously a trigger to a unresolved stress. You would not try to fix your own broken leg & should not try to fix this alone. Find a life coach/therapist that can teach you the skills needed to get past these events.

Flashbacks: This situation needs to be treated. Likely PTSD, which is a normal response to a life-threatening trauma. A clinician who specializes in PTSD can help diagnose and treat. Clinical hypnosis is a modality that can be helpful. See www.asch.net for licensed professionals who utilize this. Peace and good health.