He is playing and saying "I am boss". Stop worrying!
It sounds like its happy! When my dogs run in the yard and scratch their feet like a bull ready to pounce.... I see it as a happy, excited feeling they have....just like when humans jump up and down in joy!
If this is a new behavior then I would be concerned that there is an underlying medical or behavioral problem. Common causes of itching include mites, ringworm, allergies, hot spots, and bacterial infections. Your veterinarian may want to run a ringworm culture, skin scrape, and dermal impression smear. Treatment will be started pending diagnosis.