My dog is a german shepard mix, he's almost 10. He developed about a month ago a hard solid lump behind his shoulder blade. It doesn't hurt him or effect his mobility at all. It doesn't move or change in size. The fur around it appears fine. He's going to the vet in Sept for his checkup but just wondering if I should take him in sooner or if it's nothing major. Cause I really don't know. Tahnks!