LastRow = Cells(Rows.Count, 2).End(xlUp).Row

ActiveSheet.Shapes.AddChart2(240, xlXYScatterLines).Select
ActiveChart.SetSourceData Source:=Range("SheetName!Range")
    i.e. (SheetName!$D$2:$D" & LastRow)

ActiveChart.FullSeriesCollection(1).Trendlines.Add Type:=xlLinear, Forward _
     :=0, Backward:=0, DisplayEquation:=0, DisplayRSquared:=0, Name:= _
     "YourTrendName"

ActiveChart.SetSourceData Source:=Range(SheetName!Range)
ActiveChart.ChartTitle.Text = "Your Chart Title"

With ActiveSheet.Shapes("YourNameChartAreaName")
      .Left = Range("A" & LastRow + 2).Left
      '  Where to place the left of the chart
      .Top = Range("A" & LastRow + 2).Top
      '  Where to place the top of the chart
End With