There are many doctors who are unfamiliar with costochondritis. I was told the pain was in my head and to go on anti-depressents. I was furious...but didn't give up. You and I both know how real the pain is. If you experience the same reaction, I can't tell you what to do....but my friends, I would go to another doctor.
When most people get diagnosed, they have gone through a multitude of tests. It's often diagnosed by a process of elimination. Make sure you are cleared by a cardiologist! For me, after ruling out all auto-immune diseases, spine problems, and having bones scans, chest x-rays, Ultrasounds, MRI's, blood work and more...I found a pain management (pysiatrist) doctor who diagnosed me. I was so thankful...and the frantic search for healing began...fun. =)
How did you get diagnosed?