Been like this since Wednesday morning. What is this and how do I fix it?

I was doing fine Wednesday morning until I lifted a box to be put away. I felt tension below my sternum then shortness of breath followed by right side chest tightness, rapid heart rate and a spike in stress/anxiety. My chest is still sore to the touch and it's a bit difficult breathing, and my heart rate is still up but I haven't noticed that my condition is getting worse. I suffer from stress and GAD regularly but would this be a case of a pulled muscle as opposed to a heart problem? The box I was lifting wasn't that heavy.

I’m not a cardiologist, but I’d go to the nearest emergency room.

It’s best to get checked out, why take a chance on the possibility that it’s just a pulled muscle
when you don’t know that for sure. Get checked out.

wasn’t a panic attack, two blood lots in both lungs. Doing ok, about to head into surgery