Increased Humming sound.

Look, it's easy and quick to check if it's bearing related. Pop off the bearing cap, remove the cotter pin, back the adjuster nut off 1/4 turn and reinstall everything. Now check and see of the sounds changes. Ain't going to hurt nothing and your shop is less than professional for not at least recommending this test, unless of course they were the ones that redid the bearings.