I was diagnosed 3 years ago. Saw the orthopedic doctor as well as my GP. They did X-rays and a ct scan and found issues with my sternum. That's when they told me I had costochondritis. It is really hard when you flare up but, like everything else, it gets better and comes back with a vengeance. I've had it I long while. Eddie they could tell me what it was. Sending warm Wishes and positive vibe for good healing.
I have it with my fibro and osteoarthritis. Yeah, it sucks. It's always ached but the first time it was super bad I made my hubs take me to emergency. They were super helpful as always but at least confirmed that's what it was which is better than usual. I usually lay down with a heating pad on it when it gets super bad. **oft hugs*