Try this and see how your cutrrent setup is different from the recommendations, especiallit saddle height and knee position.

http://www.coloradocyclist.com/bikefit

The two things that need a closer look at from the pictures are your saddle height and level. We can't tell where your leg is at the bottom of the pedal movement from the picture so you might be too low. I'm basing that on the more upright position you are in being in the drops. The other thing is your saddle is pointed down. It works best for most people being level. The way you have it forces more of your weight onto your wrists and hands that also makes your shoulders tired.