What exactly is a traumatic memory?

Like, how does it form, how do you stop it from infiltrating your life? is there a process it goes through before it becomes a flashback?
how is a traumatic memory born? where does it live? why is it different from other memories?

Im just being plagued and I want to try to understand and stop it

They can be triggered by just about anything like words, sounds, smells. I get flashbacks when I hear certain things. Its just stuck in your long term memory when it happens it may or may not be a big deal but it can get worse over time. It can be traumatic right away or later on when you comprehend what really went on. It varies by person.

If you're already being tormented then the time for prevention has passed (at least for these memories). Your best bet is to push forward with trauma processing in therapy.

As a child, certain things impact you more than others. Good memories and bad alike. As you age, you might remember things both good and bad that you didn't think made an impression at the time. Just as you get a good feeling from remembering your 5th birthday party, you get bad feelings from remembering the time you were bullied. Some of these feelings can stay with you throughout your life, both the good and bad. You can learn to deal with the bad memories, feelings, thoughts, and it can get easier thru time.

Some people, like those with PTSD from war, domestic violence, rape, severe injuries, and other life changing situations have a hard time dealing with those bad memories. Some or all of the trauma can stay with them. They can learn how to cope and manage their flashbacks, and ask for help when needed.

Don't hesitate to ask for help if you need it. When you are depressed or anxious the bad memories seem to take over. They are not who you are, they are a small part of you.

I'm sure you can find some great research to help you read further to understand.....If eyes are shut there can sometimes be what is heard, what you hear your body saying as a result, the struggle of hands the body fighting back or someone's strength to over power......Why are others subjected to flashback and trauma to where it is in the mind I'm not sure. Some people don't even know what flashbacks are and can think they are normal.

traumatic memory is any memory of any content which causes you anxiety, depression, nightmares .....

example

abuse of any kind can cause someone to have anxiety,depression, nightmares, flashbacks.
natural disasters can cause a person to have anxiety, depression, nightmares.
losing ones job may be something that causes someone to have anxiety, depression....
a death in the family may cause someone to have PTSD symptoms...
work stress could be traumatizing to someone.

what is traumatic for one person may not be traumatic for another...

example it was traumatic for me when I lost my home in hurricane sandy. but for my wife losing our home was not traumatic for her, she was just glad we were all safe and were able to procure other living arrangements.

another example it was traumatic for me to be a witness to a crime but for someone else i know witnessing this same crime was not traumatic to them.

each human being has their own coping tools and what causes them to have trauma symptoms. the symptoms do not come in any special order, one person may have anxiety first where as another may have flashbacks first its all individualized depending upon ones own brain and how they think, react, and what their own bodies feel is traumatic for them.