I dont understand why the shop owner is "irritated"? Because you did some work yourself?? With all due respect F him. He says you cant tell if a ball joint is bad by putting it up on the lift and checking for play?? Really? Find a new mechanic. He's mad because you relaced all the parts he was gonna mark up(at least 2x) and now all thats left is to diagnose, tough dots! Thats kinda his job. Anyway I digres, did you get the printout from the alignment? Did everything align well? Does temperature afffect the "tugging" you are feeling?
My experience with a failing rack sounds similar but was much more noticeable on a cold morning when first hopping on the highway. What is color and condition of fluid? Have you tried flushing the rack with synthetic fluid? That made a noticeable difference in mine. Good luck.