Is there a problem for a man to wear shorts, is it written somewhere specifically. If it is within the Halacha to wear them is there some posek who permits to pray or make a bracha wearing shorts. What is the way for men to wear clothes that its tzanua (modest). what are the sources?
1. In regards to prayer, one should dress in a fashion one would meet an honored person. This also depends on the locale. At a summer camp, for instance, campers might greet a visiting senator in shorts, while at school they probably wouldn't. On a kibbutz where short pants are standard dress. it would be permittted to wear shorts to shul, but in a place where you wouldn't wear shorts to a formal gathering, they should not be worn to\for prayer. (See Orach Chayim 91, Mishna Brurah 12,13, also Beit Yosef that it depends on locale) 2. As for tzniut for men, though the guidlines are not clear, the idea should be that clothing that is provocative or demeaning is out of bounds. As indicated above, this depends a lot on the locale. It is true that there is a great deal of emphasis on tzniut for women and not enough for men. I know that some women (maybe many) are uncomfortable seeing men in shorts, and this should be a consideration.