Passion is an output. When we are involved in something deeply personal, and advance some higher purpose or cause, we feel passion. Stress is an input. When we experience something that we feel no personal connection with that is not helping advance any bigger cause, that is stress.
Passionate people frequently work many hours on a project without complaint because they feel the work is worth it. Others who are stressed from working long hours typically don’t feel the work is as worthwhile. Passion is an output, not an input. Stress is an input, not an output. So, if you find something you believe in, something you are willing and excited to put your valuable time an effort into, what you will experience is passion.