Maybe
Sub vbaexpress_52132()
Dim j As Long, jve
    For j = 1 To Cells(1, Columns.Count).End(xlToLeft).Column
        jve = Split(Cells(2, j), ",")
    Cells(2, j).Resize(UBound(jve) + 1) = Application.Transpose(jve)
Next j
End Sub