I also get this in my sternum the middle of my chest but only in the last couple of years it came about . I had never had it before but when I mentioned it to my physio she said that it’s possible to get inflammation in this area and ribs and my sister gets this symptom in her ribs a lot . I think it started for me not long after starting my job as a Health care Assistant , moving patients up the bed that kind of motion set off my pain .
Could be worth mentioning it to your Rheumatologist or doctor . Hope it settles for you soon .
Blessings .