You don’t need FindNext if you start each Find after the previous one:
Sub qwerty()
Dim rFirst As Range, r As Range
Dim A As Range
Set A = Range("A:A")
Do
If rFirst Is Nothing Then
Set rFirst = A.Find(What:=1, After:=A(1))
Set r = rFirst
Else
Set r = A.Find(What:=1, After:=r)
If r.Address = rFirst.Address Then Exit Do
End If
MyString = MyString & " " & r.Offset(0, 1)
Loop
MsgBox MyString
End Sub