The growing pains he mentioned are referring to panosteitis a/k/a "wandering lameness." It's bone inflammation, usually identifiable on an x-ray. It classically stays around for a few weeks, then goes away and comes back on a different leg. It's very common in this breed, and it should be the first possibility considered given your dog's age.
My view of elbows is NEVER consider surgery without (a) sending the images out for a tele-consultation with a board-certified radiologist, and (b) consulting with a board-certified vet orthopedist. The report you get in step (a) will tell you if you need step (b). This isn't something I'd leave to a regular vet to diagnose.
Elbow radiographs are very difficult to read. The risk of erroneous diagnosis is high -- the position REALLY matters for the x-ray, and there are lots of things going on that could cause lameness other than ED (from a carpal issue to even a broken toe). My own vet is a wonderful, but he's the one who taught me to send all elbow xrays to our state university's veterinary radiology department--he has no ego about it, knows they're a tricky joint, and values a second set of expert eyes on them.
The tele-radiology consultation is reasonable in cost -- $44 per x-ray view ($92 for CT) at LSU vet school, with digital x-rays uploaded electronically by a vet anywhere, with a report sent by email:
https://www.lsu.edu/vetmed/veterinary_hospital/services/diagnostic_imaging/teleradiology_service.php
(Any vet school could likely do this for your vet, and prices will vary. If nothing else, it gets you an inexpensive second opinion.)
If it turns out to be ED, I would definitely want a vet orthopedist creating the treatment plan. In mild cases, surgery may not even be needed! They may want to wait for the growth plates to close to see how the elbows finish developing, but that's for the ortho to decide. There are lots of "kinds" of ED, and lots of different surgical techniques that specialists use -- including arthroscopy (the same minimally invasive technique used in human knees).