I am a TA for a course but it is NOT in my list of courses in CourseWorks.

TA's are not automatically associated with course sites. In order to be associated with the course:

The instructor can add you in CourseWorks by going to the Settings section and then clicking on Set Members. Enter the UNI, select Teaching Assistant, then Add Member and Confirm.
The instructor can write to courseworks@columbia.edu requesting that we add you.
The instructor can use the link below to send a report to CourseWorks requesting that we add you.