My boy has a small hard grape size lump between his shoulder blades. Before I get too worried I was wondering if it could be his microchip that developed some scar tissue. It's the same location as the chip???

Not likely. How old is your dog?

Possibley a vaccine site reaction. Have your Vet take a look at it.

Get a needle biopsy of this lump immediately. A friend of mine found such a lump between shoulder blades and it was a very aggressive malignancy.

Hope your boy is fine. Early action is helpful, and good for you in finding a lump in such an unusual place. My friend's dog is still going strong so far.

I just had the same thing shortly after microchipping a puppy. It got progressively smaller over a few days.

Mike

Could also be an impacted oil gland around a hair folicle. My girl had a similar size bump and the vet confirmed the above