I have an application that was made for me in labview. I have paid for it and the program works well, I need to know if I should be recieving source code with the program so that I can alter it in the future.
Once the executable is built, you can NOT extract the source code from anymore. So if you do want to modify the program at some point, you WILL need the source code. So YES indeed, you have to agree with your software supplier that source code becomes your property @ delivery and acceptance.
thats what Im doing. do I need source code or is the program built so that it can be manipulated from the end users code?
That depends on what you mean by manipulated. Like any .exe build in C, C# or LV it can support alot of modifications and ini-files and the like if built around it. If you want to change how the program works in the core you'll need the source code. That's the same for all programming languages.