This is Dr. David
I am sorry you are having more piercing pain down your left lower back into your left leg.
you could be developing scar tissue in the area of prior back surgery which can put pressure on the nerves there and cause a return of stenosis and pressure on the nerves.
you might need to go back to your surgeons and ask for an MRI scan of your lumbar region to check for scar tissue and inflammation of the nerves and nerve root compression again.
there is not much you can do to prevent scar tissue formation in the area of prior surgery.
ask for a follow up MRI scan of the lumbar and sacral spine with contrast to see if anything new can be seen
have you had an MRI scan recently?