What Triggered the workflow

If you want to manually check this, and have versioning enabled then you could check the version history. If you want it covered in the workflow, then you either:

• use hidden (Nintex ?) form fields/columns to keep track of the previous values. At the end of the change triggering wf you copy all the required fields into these prev_value fields.
• create a simple kick-off workflow per changed column for the real workflow (no longer triggered by change event). So WF_Field01_Changes, WF_Field02_Changes etc (starting if pref value of field has changed compared to the current) which then call WF_MyWorkflow. Only of interest for small lists