Totally Orange, I hear ya too! My ds is 4 and 1/2 months old and is a very strong boy. When I am nursing him he likes to wind up and smash his fist against my chest or face. Sometimes I get a fingernail scrap down my skin that actually draws blood. I have "passed" him off to people many times just so I don't have to feel him hit me or kick at my stomach and boobs or wiggle around constantly anymore. This is perfectly normal though. My first ds did this as well and by the time they are about 18 and out of the house it will stop! LOL
All joking aside though, I think Caden was about 8 or 9 months old when this stopped but then a whole new set of issues started. There will always be one thing or another. Just try to focus on the smiles and coos and wet kisses.