My opt expired on sept 2 2014 .i am working and i applied for stem extension on june 27 and am waiting for my stem extension. Problem is i lost my expired EAD. Will i need it in future? Or its of no use once i get my stem extension opt? Any input would be highly apprecuated. Also my drivers lic expired with opt expire date. Can i get license renewal with opt extension pending . I have not tried i would be really grateful if anyone have some inputs. Thanks btw am in Tx.

If you have already applied then you don't need your EAD anymore. You will be getting a new one shortly.
As for the license, you need to have EAD to get one. I tried it once and they didn't accept the receipt of EAD as it clearly states, "This notice doesn't grant immigartion......".
So, wait for your EAD then go to renew your drivers license.