This works, replace  my "gggg" etc. with your variables. Tere are no
checks to see whether it finds something in the first column, when it
would have difficulty putting anything in the cell  to the left!:

Sub Blah()
Set c = Cells.Find(What:="gggg", LookIn:=xlFormulas, LookAt:= _
xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext,
MatchCase:=False _
, SearchFormat:=False)
If Not c Is Nothing Then
Do
c.Replace What:="gggg", Replacement:="aaaa", LookAt:=xlPart, _
SearchOrder:=xlByRows, MatchCase:=False,
SearchFormat:=False, _
ReplaceFormat:=False
c.Offset(0, -1) = "6Descriptive text"
Set c = Cells.FindNext(c)
Loop While Not c Is Nothing
End If
End Sub

I had to ditch the loop because it gets stuck and goes around for
ever, but without the loop it works fine. A couple of the offset
replacements don't seem to want to replace  for some strange reason,
but your code  was a huge help and I think I can take it from here.