Private Sub UserForm_Activate()
Dim i As Integer
Dim arrFIO(21)
Dim TxtFio(20) As Object
Dim ChKFio(20) As Object
Dim countT As Integer

countT = 0
For i = 0 To 20
    If Cells(i + 5, 3).Value = "a" Then 'если в столбце "С" стоит галочка
        arrFIO(i) = Cells(i + 5, 2) 'добавляю в массив фамилию из столбца "B",отмеченную галочкой
        Set TxtFio(i) = Me.Controls("Frame1").Add("Forms.TextBox.1") 'добавляю на форму TextBox
        Set ChKFio(i) = Me.Controls("Frame1").Add("forms.CheckBox.1") 'добавляю на форму CheckBox
           With TxtFio(i) 'задаю параметры TextBox
                .Top = 20 + 16 * countT
                .Height = 16
                .Left = 10
                .Width = 100
                .Text = arrFIO(i) 'записываю в TextBox из массива arrFIO
           End With
           With ChKFio(i) 'задаю параметры CheckBox
                .Top = 20 + 16 * countT
                .Height = 16
                .Left = 10 + 102
                .Width = 100
                .Caption = (i)
           End With
           countT = countT + 1
    End If
    Next
End Sub

Private Sub UserForm_Click()
Dim X As Object
Dim chk As String
    For i = 0 To Me.Frame1.Controls.count - 1
       For Each X In Me.Frame1.Controls
           If X.TabIndex = i Then
               If TypeOf Me.Frame1.Controls(i) Is MSForms.CheckBox Then 'проверка, что это CheckBox
                    If Me.Frame1.Controls("CheckBox" & i).Value = True Then '3
                    chk = "CheckBox" & i
                    MsgBox chk
                    End If
                End If
            End If
        Next
    Next
End Sub