Chicken breast meat is white because of lack of blood flow and the accompaning capillaries in it as the muscle is not used much. Game birds who fly have redder meat because of the opposite. I suspect that it is the same for pork. Leg muscles are intensively used and so have a rich supply of blood. The body muscles of the pig are used less intensive and so are whiter. Ham is from the leg, pork chops from the body.

By cooked ham I assume you mean cooked, cured ham rather than just roasted meat from the ham of a pig.  The curing process will affect the final colour.  Also, a lot of commercially available cooked ham has colour added during the processing to provide a more uniform appearance.  This reduces the effect described in a previous answer where colour can be affected by factors like exercise.  Read the contents list on the ham you buy and look for colouring ingredients.  If possible, compare the colour with more expensive products, particularly organic, which probably won't have colour added.

As previously stated, the ham comes from a well used area of a pig. However it is not the high blood flow giving the pinker colour, but instead the high number of mitochondria (a cells 'energy factory'). The muscles in the thigh of a wild pig are not really designed for long distance, high stamina exercise (unlike the white pectoral muscles/breast meat of a bird). They were originally evolved as a means to escape predators, and in this case that means running fast for a relatively short distance. As the use of the muscles is rapid, energy is required very quickly. Available oxygen is quickly used up, requiring the use of anaerobic (without oxygen) respiration and anaerobic respiration is far less efficient than aerobic (with oxygen), and therefore a considerably higher number of mitochondria are required.