countif loop through range

I'm having trouble with my variable range for my countif.

I am trying to loop through the range A4:A (bottom row based on Brow). one cell at a time (j) but I am having trouble setting the range for the countif.

Can anyone suggest what I am doing incorrectly so I may recitfy the code?

Sub checkPensionColumns()

With ThisWorkbook.Sheets(3)
    Brow = .Range("A" & .Rows.Count).End(xlUp).Row
    BCol = .Cells(3, .Columns.Count).End(xlToLeft).Column
        Set BeforeRange = .Range(.Cells(4, 1), .Cells(Brow, BCol))
End With

Set myrange = BeforeRange
    For j = 4 To myrange.Rows.Count
    Debug.Print j
    Debug.Print Brow
        If Application.WorksheetFunction.CountIf(Sheets(3).Range("A4:A" & Brow), myrange.Range(A, j)) > 1 Then
            With ThisWorkbook.Sheets(2)
                LRow = .Cells(.Rows.Count, 2).End(xlUp).Row + 1
            End With
                ThisWorkbook.Sheets(2).Cells(LRow, 3).Value = myrange.Cells(j, 1).Address
        End If
    Next j
    
MsgBox "Sub end"
End Sub