My daughter was crazy with the screaming and the tantrums at that age (we are at 14 months now). I searched far and wide for the answer, and by the time I found something credible, the stage had passed.
From what I read, kids at this age have a very difficult time communicating. This frustration normally turns into rage....rage into screaming....and there you go! The best advise that I found on this subject was to teach your child sign language. For those in the working world, teaching sign language is a bit of a stretch. So I chose a happy medium and just began better communication with my daughter. You will be surprised how much your son understands. I chose to do a "play by play" of things i was doing with Ruby. "I'm going to change your diaper now"...."You need to sit up now honey"...."Mommy is peeling your banana and then you may have it." I think my daughter became engaged in the conversation, understood part of what I was saying, etc. At this point they want to gain this independence (aka Ego), but don't yet have the tools to do it. The "play by play" method was the best of both worlds. I still had the control as Mom, but she was in on what was coming next, and I think that gave her a feeling of independence.
I hope this helps!!