Does excessive, but not forceful, continuous movement back and forth, and right and left, during the recitation of Al-Fatiha in prayer invalidate the prayer?

The cure for obsessive thoughts is to ignore them and pay them no attention. Slight movement in prayer is excused, and so is extensive movement if it is for a necessity. If this movement is extensive and involuntary due to obsessive thoughts, it does not harm you and does not affect the validity of your prayer. However, you must strive to repel these obsessive thoughts.