Advisor professor asks for my dissertation research source code
One of the reasons Science has been so successful is that scientists treat knowledge and tools as public goods. We don't hoard knowledge, but rather we write papers, share techniques, offer suggestions, etc. There are certainly cases in which sharing isn't beneficial, but these seem not to apply here. So of course you should share your computer program! You should share it with people you like, people you don't like, and people you don't even know.