Lump or just a bruise on my dog?

I would definitely take him to a vet as soon as possible. Dogs aren't supposed to have lumps. So any kind of lump is a bad lump on a dog. Please, just take him to the vet to have it checked out. It could be a tumor or some kind of cancer. The fact that it doesn't bother him might be good but i'd still like a vet's opinion on it. I hope everything's okay with him.