This is not the question of "should", it's a question of what you WANT to do.

If your major goal is to get more information about whether your therapist behaved unethically, you can browse through the following websites:Therapy Consumer Guide | An Educational Portal for Consumers of Mental Health Services and TELL: Therapy Exploitation Link Line for more information.

If your goal is to serve justice through filing a board complaint or a lawsuit, you can also find some info about that on the websites above and talk to someone directly through the websites' contact forms.

I am not sure what you mean by saying you'd like to find out the reason for your therapist's unethical actions. You mean you want to understand her personal reasons for why she did whatever she did? What does it have to do with any civil action you are contemplating against her and how is this going to help you in any way, not to mention that it's an impossible task?