Is there a left luggage or storage lockers at the Shanghai airport

If you mean the Pudong airport, there are are lockers for using. They are located at the exit of International Arrival Hall.

Thanks Laura, want to go into the city on the fast train for a couple of hours - taking out time for checkin have about 4 hours - any ideas of must see?? I am planning to visit for a longer time later, but just want to experience Shanghai for a couple of hours.

You mean you only have about four hours for city sightseeing?
If so, I do not think it is a good idea to travel around, because the time is so tight.
If you really want to, you can take the maglev train to Longyang Road Station and change to line 2 to Lujiazui Station. Then you can visit the Oriental Pearl Tower and the wander around the Binjiang Park to see the Huangpu River.