I've been feeling this pinching kind of mild pain on the left side of my chest that lasts for like 46 seconds or so. At those moments, I can really feel my heart beating faster when I put my hand on my chest. I did talk to a cardiologist about it, and they recommended an ECG, which turned out normal. But I'm still really worried. Could these be warning signs, and should I consider getting more heart-related tests just to be on the safe side?

Given your symptoms of intermittent, mild, left-sided chest pain lasting 4-6 seconds, accompanied by an awareness of a rapid heartbeat, and a normal ECG result, your cardiologist may recommend further tests, such as a stress test, echocardiogram, or Holter monitoring, to rule out potential causes like arrhythmias, pericarditis, or cardiac anxiety, and provide reassurance, but in the meantime, pay attention to any triggers or patterns, and consider maintaining a symptom journal to discuss with your doctor.