Thank all of you for the answers. My breathing problems are not everyday. My is more like a tightness. I feel that sometimes it’s anxiety because if I get busy with something and not think about it then I’m fine.
Other times it just starts out of the blue. And of course that makes me anxious.

To all on this topic: After getting heart and lungs and spine thoroughly examined with all the MRIs and tests, costochondroitis is the diagnosis. Inflammation of the soft tissues that connect ribs to spine in back and to sternum in front. To make matters worse, when we arent exercising hard enough to get us breathing hard, due to other pains and surgery recovery etc, we tend to breathe more shallowly more often. Two years ago mine was so extreme that i couldn't speak loudly enough to be heard over any level of background noise or in a large room. The diaphragm must be engaged on a regular basis to keep the ribcage flexible. I began 10 rounds of deep diaphragmatic breathing exercises twice a day. There are plenty of guided videos and descriptions how to do this online. After a year my ability to project my voice has returned and i have not had a costochondroitis flare in over a year now. As with all our physical therapy exercises to improve function and reduce pain, it must be done consistently. This is one exercise that can be done anywhere at any time. Any of you who want rid of this nuisance and to avoid eventually caring an oxygen canister around, you will do this every day. 🙏🎄🥳

my Costochondritis comes and goes and makes it challenging to keep a steady exercise routine.

It happens as the joints in the rib cage fuse together. Mine happened in 2000.

From my understanding, it's due to the inflammation in the places where ribs and the middle breast bone meets