Check out the symptoms for costochronditis....I get it regularly and it almost fools me into thinking I'm having a heart attack.

I think my rheumatologist who I just saw ruled out lungs with a pulmonary referral/test but that was a year ago before symptoms started. and my primary ruled out with an EKG. I’m not considered high risk for heart issues due to low cholesterol and low blood pressure. And no family history. All of my labs for inflammation, etc. are in the normal range. But something is definitely unusual. Maybe I just need to be more insistent.

Sorry, just saw ur other post with more details

U need to immediately rule out heart then lung issues, then see your rheumatologist. RA can affect internal organs iin some cases.