What is this movie named based on the plot line?

I only vaguely remember the plot line but it's where all the main characters lives are entwined and they don't even know it. I remember there's a doctor who buys blanks for her father's gun (who owns a convenience store) and he goes to shoot I think the painter who has a wife and daughter at home. I just can't remember exactly and I've been trying to remember for months!