I punched a person monday and today is wednesday and the top of my hand is swollen I can move all my fingers but when I make a fist there is pressure in the middle... there is no pain unless I try to use hand..... what should I do??

Xray. If you have swelling in your hand after punching someone and pain with movement or making a fist - would recommend being seen by a physician to make sure you haven't broken a bone.
Pain after punch. sounds like you need to go get an X-ray to rule out a fracture of your hand. Movement does not rule out a fracture. Depending on where the fracture may be, it may result in loss of function or chronic pain if not properly treated. Go see your doctor for evaluation promptly.