what does sho ga nai mean? Shiran?
I assume you mean "Shō ga nai," which is an alternative spelling of a common Japanese phrase "shikata ga nai" which translates roughly to "there's nothing to be done." It's a phrase which isn't quite so pessimistic as it sounds, though. The phrase is more along the lines of endurance and perseverance in the face of adversity. Presumably this is what was written on the front of the newspapers the day after the Fukushima disaster in 2011. It means, more than anything: we/I will go on.
It more or less means to not shave/slice off material, like when sharpening something, or when shaving something like your face or legs, or to not dampen or weaken a mood when used to describe more abstract things, but without context we can't easily tell which is intended.
See the plain negative infliction of this: http://jisho.org/search/%E3%81%9D%E3%81%90
Update, it could also be 仕様が無い as G-Cam mentioned, which would be written as 'shyou ga nai' not 'sho ga nai'.
It literally translates to 'The way does not exist', which is the Japanese way of saying 'There is no way' in the sense that something cannot be avoided, it will happen, there's nothing you can do, things like that.
See this expression here: http://jisho.org/search/%E4%BB%95%E6%A7%98%E3%81%8C%E7%84%A1%E3%81%84
Hope this helps lad. :D