Co worker yelled at me then grabbed my wrist to hold me so I would listen to her. I asked her to let go and she did not, then I asked again firmly, Let go of me Now!
I reported the incident and she did not deny it. It was investigated by HR and they let her keep her job, I feel it is unfair and I am afraid to be around her
You could have called "911" and reported the battery she committed upon your person.
You decided to report it to your employer, and you have to live with that choice.
An employer has no duty to do anything when you complain, yours chose to investigate.
Apparently the matter was addressed, and you have no right to know what the employer did to the other person.
Heck, the employer may have given the other party a bonus for roughing you up, but you'll never know.
If you feel unsafe you can always quit and find a safer job with a better employer making more money.
If you can't and you want a paycheck, then you have to shut up, grin, and pretend you like it.
You know that lie parents say, "I love all my kids the same."
Its a lie, because we love some people more because they are more like us.
Employers like some employees better than others.
At any rate, its over, so its time to move on and do what you were hired to do to get paid.