I was curious about pawpaws, even wrote an article for Dave's Garden, which convinced me not to try growing them in my yard. They are actually very common in woods in my area when you learn to ID them. They are found very close to rivers or streams, under other trees, and I have seen them bloom but finding a ripe fruit is elusive. I once saw ripe fruit fallen at Flag Ponds in Calvert Co, MD, since then I am never there at the right time, or never see developing fruit on the trees- lots of fruitless leafy branches.
ElPollo is right.
I think pear and cherry are supposed to be less problematic around here than some. I tried peach and plum, cannot commit to spraying and proper pruning, and brown rot took over.