Looks like a robin but black head very spotted on chest and stomach also on the back of the wings?

Based on your description, it sounds like you might be observing a European Starling. These birds have a black head with a speckled or spotted chest and stomach, especially during the breeding season when their plumage is particularly vibrant. Their wings also display spots, and they are known for their iridescent feathers. If you're in North America, it could also be a juvenile or female American Robin, which has a more muted coloration.