I'm betting that Triton trailer has a torsion axle that is welded on. Sadly, some factory-rigged single axle trailers offer little margin for the load that is put on them once you consider the realities of added weight. The axle (often 3500# rated) must support more than just the boat hull. The trailer's weight must be included along with the outboard, trolling motor, batteries, all tackle/gear, and fuel (6 lbs./gal.).
When I needed trailer alignment, I've had good luck with truck & frame shops. Alignment on most heavy trucks is done by controlled bending of the frame and/or axle. The same process and set-up is used to align a trailer. I've never found a trailer shop that had invested in the laser alignment gear used to properly align the tires.