It is difficult to give you an accurate diagnosis based upon one picture and two sentences. The photo looks like a fungal disease called Pseudomonas. This is common in many plants, including fruit trees. I don't know what variety of pear you have but some are resistant to this. Resistance doesn't mean the tree won't get it. It just means that it has defenses to combat an onslaught of the spores. Trees usually get infected in late winter or early spring when the spores are splashed onto them by the rains. You usually won't see any signs until the summer when the soil dries out and the tree getsstressed by drought. This is a very dry year and you should be watering your trees deeply every two weeks or so,depending upon your soil conditions. Your need to physically check the soil (don't guess). Dig down at the drip line about 10 or 12 inches and grab some soil. Is it moist? If it's not deep soak slowly around the drip line.
   Pseudomonas can be controlled with sanitation, proper pruning and dormant spray schedule. Refer to OSU Extension publication ec 631 which can be  Googled and downloaded.
   If you water your pears should ripen just fine.