You forgot to close a parenthesis, so from the last open parenthesis, PHP considers all the code that follows as part of a specific block (condition, arguments of functions etc) that does not end. You ...
No, you don’t need an IDE to code in PHP language, you can code in Notepad and be all good. But trust me, you wouldn’t want to go that route as you have to put in a lot of extra and unnecessary work ...