health

Question
we have a yellow lab with a knot on the right side , about middle of rib cage. the knot is about the size of a golf ball. the dog is not in pain. what could this be?

Answer
This is a bit beyond my expertise, however lumps of any kind aren't something I'd fool around with. Get this puppy to the vet and have him check it out as soon as you can.  Cancer is very common in large breeds that usually start out at lumps.  good luck!  :)