I had three bouts of it 10 years apart in my 20’s , 30’s and 40’s. Many causes for it . The one in my 20’s I’m pretty sure was viral in nature causing inflammation of the cartilage attaching ribs to sternum .
The on in my 30’s was impact related , kicked in the chest at work .
The one in 40’s was overuse while trying to get into shape after a health scare.
The first bout was the most painful and hurt to move or even take a deep breath. Sharp deep pains from front to back .
Like you I don’t like to take pain meds or
anti-inflammatory meds if I don’t have to but it was necessary. It was usually prescribed 6 or 8 hundred milligram motrin for a short duration . During that first bout I suffered for two months before seeing the doc because I thought I pulled something . After 3 -5 days of the Motrin it was gone . Inflammation begets more inflammation even with rest in many cases . So I took the meds and it disappeared fast !!!
It’s a bit over 15 years since the last episode .
Shallow breathing and not fully expanding the rib cage can cause it also . There’s no full range for awhile then you do something beyond the full current range of the ribs and sternum and bam …… it’s back . I’ve done stretches and deep breathing exercises since the last episode and since learning more and have been good since .
IT IS severely painful . It was for me a sharp tearing pain worse than my widow maker heart attack this past January which was painful but more an intense center chest soreness. My advice ( but speak to your doctor) is take the anti inflammatory and once inflammation is gone and your healed up look up breathing exercises and stretches for costochondritis . Good luck and heal fast