Is there a way to trace out some text, or fire a pop up alert in unity to make sure you are getting into a specified function or get the value of specific variables?
Michael's answer is correct, but for showing variable values, there is another option that I recently found. You can put the Inspector into Debug mode (via the drop-down triangle on the right side), which lets you see all variables in a script, not just the public ones.
They do have to be permanent variables, declared outside of a function (if you declared a temporary var in Start(), for instance, it would be gone). But they don't have to be declared public, to be visible in Debug mode.