You can tenderize it by mechanical or chemical means.
Adolph's Meat Tenderizer, a product available in supermarkets, contains a natural enzyme extracted for papaya and pineapple, that will tenderize the meat. Marinating in dairy, especially yogurt, will also do some tenderizing.
A jacarding tool, a device with sharp metal points used to repeatedly stab the meat to break up muscle fibers will also work to tenderize the meat. Pounding it with a meat mallet will also work. Use the side with the pyramid shaped points.
Cooking it to medium well does not help the situation. If you cooked it a bit less, say to medium, you would have better results.
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan