Is being bored a good reason to quit a job?

Job anxiety. You need to make sure your boredom is not a part of the way you typically feel and would be present in any job you have. Talk with a close friend about this tendency and ask for truthful feedback. Best.
Yes. Boredom means that you are not being challenged or stimulated mentally or physically. This is not just a "bad job" -- it can have profound effects on your mental and physical health. Find something that you're passionate about -- that you could talk about for an hour and not be bored -- and pursue a career in this area. Your body and mind will thank you! best of luck!