Yes, there is nothing worse than doing a Google search for symptoms when you are already worried.
There are many things these lumps could be. But of course only a vet can find out and tell you. A fine-needle aspiration can usually tell if they are fatty lumps or fluid-filled cysts for example.
Your dog won't need an anesthetic for a needle-biopsy.
These are not ever 100% foolproof, but can often tell quite quickly if the lumps are definitely "benign" (harmless)
But it is also possible this is mammary cancer and that you have to be prepared for.
The good news is this: If it hasn't metastasized (spread to other organs) then surgery alone is usually a cure! But how much surgery....depends on the extent of the affected mammary tissue.
Sometimes, especially if caught early, removal of the lumps themselves will be enough.
But if there is other tissue which the vet doesn't like the look of, then a half mammary-strip may be the best solution.
Dogs have two sets of mammary glands; the lower set and the higher set. These are not on the same "system", and are linked to different sets of lymph nodes (in the groin, and also in the armpits)
So very often if suspect tissue is found in say -the lower set of mammary glands, this can be unconnected to the upper set.
So even if a mammary strip is recommended, it usually ends up being a "half-strip".
My own dog survived mammary cancer excellently with no return of it. She was 14 when she had the surgery, and was chasing the frisbee again after her restricted exercise period was over!
Your other issue obviously -is the cost (if needed) It will cost a few hundred dollars/pounds. etc
So also do what you can to be prepared for that, such as organising funding for it by any means.