Whenever i run my map it is all black

Looks like a leak. Is your map sealed all the way around?

then you have a leak obviouslly

You can see if you have a leak by looking at your compile log (the window that pops up when compiling your map), which is also available after your compile where you saved your vmf file, and is named the same as your map, but ends with .log instead.
To help with fixing leaks, go into hammer and in the Map menu in the menu bar you will find Load Point File. Click this and it will show you the path the compiler took to link an entity to the void. Fix this by placing a world brush to fill in the hole.
If you need more information, check the Valve Developer Community website.