A few months ago, I had pain in my left chest. I was referred to a cardiologist just in case it was a heart problem. All the tests, including CT, treadmill, echo, and 24-hour Holter returned negative. I was informed that it was likely being sports injury, possibly tennis, and nothing to worry about. This pain has been a kind of on and off and I wonder if there is any way to help my muscle to heal. Should I have this further investigated by a specialist?