Create an Array from Excel formula

It would help if we had a clue what you're trying to do and what ="{"&Col.Header&"Paid"&"}" is supposed to mean.

Do you mean to create an array formula in a cell using VBA? If so, use the FormulaArray property.

Here's an example:

    Cells(3, "F").FormulaArray = "=R2C10:R2C20 * R[-1]C10:R[-1]C20"

Curly brackets are not needed in the VBA code but will appear in the generated formula.

An another issue, the ampersand normally should have a space before it when your intent is to concatenate values.
(When an & appears at the end of a variable, it signifies a 'Long' type variable.

Plus, don't forget to include a space (or hyphen, etc.) to improve readability in the generated code

ex

  Cell(2,Col).FormatArray = Col.Header & " - Paid"

But as shg suggested, we really need to know much more about your program's intent before answering further.
Please describe in detail what you are trying, including the data both before and after the macro; If possible, attach a sample workbook with your (desensitized) data.

Do you want to defined a named range using VBA? That can be done. . .
Try recording an example to see the generated code; then adapt as needed.
Note that RC references in the macro recorder.

Here's what I got . . .

Sub MakeRange()
'
    Range("D9:D17").Select   
    ActiveWorkbook.Names.Add  Name:="MyRange1",  RefersToR1C1:="=Sheet1!R9C4:R17C4"
End Sub

Notes:
1. The Range(. . .).Select instruction is not needed.

2. The RefersToR1C1 parameter may be replaced by the RefersTo parameter with a regular range indication.
example:

Sub MakeRange()
    ActiveWorkbook.Names.Add  Name:="MyRange1",  RefersTo:="=Sheet1!D9:D17"
End Sub