Yes, the method I use is
3 breaths through the nose and 6 out mouth, like you are blowing out candles.
This is supposed to relax and sends an message to my nervous system that all is well. Dr. V .
Helped me.
I take 3 when I feel like I can't catch my breath.
Take care.
Lila Redeagle

Yes! I experience this often

The stress from the pain often causes shallow breathing. Mindful deep breaths inhale to the count of 6, hold for 4 seconds exhale to the count of 5. Doing this 3 times a day to start has helped me increace my lung volume and calm down considerably. I didn't realize that my " fight or flight was engaged consistantly. Practicing this method and increasing the length of both inhalation and exhaling has helped me obtain results pretty quickly. I don't need to practice anymore but I'm definitely aware when I encounter unexpected stress or my pain is at an obnoxious level. Hang in there! Big gentle hugs

Yes when i have costochronditis (sp)

Yep a lot of anxiety is from or caused by that