I took a long knife and went between the window molding to get to the inner workings of the door and kept pushing nand hitting while hitting the outer button until it opened, it sometimes takes awhile but it is a lot easier than taking the panel off and you cant get in anyway. After you get it open spray everything with WD40 .

i had this prob with my 90 sse. i took the interior door panel off and sprayed the crap out of the lock (behind the handle). you have to get all the crap out.
the other side stuck as well and i did the same there. eventually on of the doors had a rod come loose from the plastic clip it sits in. got that back together (i have tiny fingers and havent had any problems since.