Populate Multiple Select ListBox

I am trying to populate a listBox with data from cells. I eventually want to be able to make the cells change by just adding more data into my worksheet.

Here is my code. It should fill my listBox with just cells A1:A11 (I can't figure out how to make it adjust for new data), however the code is returning this error:
"Run-time error '91'
Object variable or With block variable not set"


Option Explicit
Sub PopulateListBox()
Dim myList As Worksheet
Dim x As Variant
For Each x In myList.Range("A1:A11")

UserForm3.ListBox1.AddItem x.Value

Next
UserForm3.Show
End Sub