Totally agree. Any suspicious lump should be Vet checked and possibly at least aspirated. Not sure what you mean by boils but this seems like a pretty young dog to be having these issues, ore the reason to have him checked.
It is very likely to be, but please don't take my word for it. Get the lump checked out as soon as the vets open after the Christmas break. It is always worth getting them seen as soon as possible, either to set your mind at rest, -or in the worst-case scenario, to get the lump removed as soon as possible.