When you get to the vet, make sure they do a fine-needle aspirate to see what sort of cells are in it, unless they recommend immediate removal. It's virtually impossible to diagnose a lump without looking at the internal cells, so don't let them tell you differently.
The aspirate will be the cheapest option, but mostly it will depend on your vets comfort level. Some vets recommend immediate removal of lumps without intermediary diagnostic tests, some prefer to do the aspirate first to see what they're dealing with.
Good luck getting it figured out. It seems to me that goldens tend to be prone to fatty lumps, so hopefully that will be the case with him, and a quick removal will solve the issue!
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"Courage is resistance to fear, mastery of fear, not abscence of fear."
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The problem with the gene pool is that there is no lifeguard.
"In my dreams, I was drowning my sorrows, but my sorrows they learned to swim" U2
