Chest pain behind sternum. Or angina?

I was covid negative around 6 weeks back (home isolation). Sometimes now, I experienced chest pain (in the Center of chest behind sternum). Some situations- I was giving an interview yesterday , I was nervous and also was continuously speaking for 25-30 mins , I got pain which was relieved when I lied down silently. Second situation - I felt slight pain while holding weight (10 kg)and carrying it. Although I don't have any problem on climbing stairs (20 stairs for my room). I got my ecg 2 times and echo done and it was fine. Cardio doctor said it may be due to muscular pain due to covid which hurt when you exert pressure . Can it be just muscular pain or angina ? I did my TMT just before covid (17th April ) and it was completely negative. Although after covid my cholesterol has slightly increased - total 197, hdl 58 ldl , VLDL -20 . Can I have heart blockage due to covid even when TMT was normal before covid or it's just muscle pain. I live in small city and here we don't have TMT.