I have made a bash that starts Chromium to a URL and full screen, if I run the bash from the terminal it works fine, but if I put it in application start it does not run.
If you are running the bash from a terminal and it works fine but not when you run it at startup, it may be as a consequence of a "race condition". A race condition is where some things get missed due to too many thing trying to start at the same time at startup. One solution to this is to insert a sleep command into your bash to delay it slightly. For example:
There is a built-in "Delay" option for startup programs in the startup applications preferences when you press on edit. I think it would be better to use that in case you want to run the bash script after startup and don't want to wait.