Try sed with i (insert command):
$ cat file | sed -e '/TEXT/ i COMMENT'

$ cat logfile
Ex : LINE 1 xxxxx
LINE 2 xxxx CALL xxxx
LINE 3 xxxx PERFORM UNTIL
$ cat logfile | sed -e '/CALL/ i COMMENT'
Ex : LINE 1 xxxxx
COMMENT
LINE 2 xxxx CALL xxxx
LINE 3 xxxx PERFORM UNTIL