Most common culprits are the inner and/or the outer tie rods and ends.
If you are uncomfortable checking these yourself, most chain repair shops will perform a complimentary inspection in the hope that they will get the repair work for any faults found. However, caveat emptor less you get take for a ride. I had a local Meineke shop try that to me when I took my 89 in this spring for an alignment after replacing the rack. They tried telling me that the brand new tie rods and ends were too loose and there was a bad wheel bearing (at least they got that one correct) and that it would be over $800 to repair. I told them to drive the car out of the shop, lock the keys in it, and to not touch it again.
Steve