My doctor did ECG and a chest xray and said

Patient: My doctor did ECG and a chest xray and said it’s costochondritis. The pain is mainly on the left side and stays there like a dull aching pain and the end tip of my sternum also hurts slightly. I don’t have any trouble in swallowing and breathing. So will I be fine? I looked up in Google and once cancer cane up with different other diseases. When I don’t pay attention to the pain it stays fine. But when I think of that result Google gave I get anxious. What should I do?

Symptoms: Pain in the sternum mainly at the last joint to the left. And also a dull and sharp pain when I move or lift things on the left chest wall.

Doctor: