Boxwood problems are many and varied. Some problems like decline can not be cured. Other problems can be mitigated but require a lot of work and monitoring to restore the health of the plant. It's difficult to make an accurate diagnosis for the specific problem or problems affecting your plants. I have attached a couple of links to fact sheets on boxwood problems that might allow you to do some self diagnosis. You might also want to clip a couple of small affected branches and bag them and take to your local extension office in Montgomery County for further analysis.

 Here are the suggested links.
http://extension.psu.edu/pests/plant-diseases/all-fact-sheets/boxwood-diseases

 https://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG52_IPM_Boxwood.pdf