I don't think Dr. Sarno said forgiveness is a necessary part of healing TMS. (Sarno experts please let me know if I am wrong.) You just need to be aware of your feelings and allow yourself to feel them. It sounds like you are doing this. Remind yourself that you are human and it is human to feel anger. Allow it, feel it, and let it go. The "let it go" part may be what you are having difficulty with, and this part could be described as forgiveness. Without this last step, our thoughts can keep the anger alive, resulting in continually feeling angry. So I think that letting go of anger, or forgiveness, is necessary for peace of mind and a good quality of life. I would suggest feeling the anger in your body and letting it pass through you. Then look closely at your thoughts that follow and see if these thoughts are stoking the embers of your anger. If so, the way to let them go is though practicing mindfulness in the present moment. Stop telling yourself the story that is stoking the flames of your anger. Get lost in the present moment--in my opinion forgiveness occurs by being present. All those grievances that are stoking your anger occurred in the past. It is over. Let it go. Be kind to yourself.