What are your thoughts on getting a second opinion from another cardiologist?

Had stents done by one and over a year now still having central pain ! Thinking it might be muscular skeletal, was told by friends get a second opinion from a DO in cardiology. They wont allow this without having the Okay r referral from my regular cardiologist. This would be a conflict of interest because I never stated I wanted another cardiologist, I just want a conciltation on what the another person in cardiology, thinks the pain might be coming from, since my regular cardio says it isnt the heart causing the pain. So just wondering., since the other is a DO