/// Start with the basics. Is there a stuck caliper? The Volvo three wheel brake circuit system causes steering when a rear caliper freezes or when a front caliper is stuck and does not relax after the brakes are applied, or when one circuit fails. There is a chemical reaction between American Dot 3 and Girling brake seals that will cause this problem. Look at the brake fluid and see if it is black or dark brown and opaque. It should be clear and amber although it darkens with moisture content. (NOTE this only applies to Girling systems.)

As a former tire store manager I can tell you that there are tire failures and defects that will cause steering. The complete failure of a belt in a front tire will cause this steering. With your post it would be inside the left tire or outside the right. I can post directions for you to self test but a shop radial runout gauge is best.

Rear bushings can cause steering if they are loose, worn out. Maybe this is the reason the alignment tech suggested the frame shop. The front to rear alignment is out. He should have spotted worn bushings, defective tires, or bad brakes and not done a front end alignment. He should not have done any alignment if the frame is bent from wreck damage. It would have to be done over if there is such damage. In this case, wreck damage, alignment is useless.

Make a decision on using this shop again based on the final solution of the problem.