Can i take st johns wort with chamomile?

Yes you can, but: I'm more concerned about the "chest pain, chest pressure, and difficulty breathing" you've also mentioned? Those don't generally respond to st. John's wort or chamomile, unless they're for sure related to anxiety (which they can be). Many people take chamomile as a tea, and st. John's wort as a standardized extract or capsule. Regardless, please follow closely with your doctor.