I agree, you need to get a check-up with a doctor. An electrocardiogarm (EKG or ECG) is non intrusive and the lowest cost of the many tests that can be run on the heart.
Try to relax and many of us take a low dose (or 1/2 a regular) aspirin a day to provide some heart benefits. Some people can not take aspirin and I do not know if your symptoms would be reduced or aggravated by aspirin. My guess is the aspirin would not have any noticeable affect, but would still provide some benefits.
You are describing typical symptoms of myocarditis (inflammation of cardiac wall). The chest pain that increases in some position and which sometimes interferes with respiration indicates that you might have this condition.
An EKG is the method of choice to diagnose it. It’s not dangerous if treated properly, so you need to have an appointment with your doctor quickly.
If the EKG revealed nothing suspicious, you might just have some kind of muscle spasm in the chest or an inflammation of the esophagus, which do not necessitate any worry and can be treated easily.
Let us hear from you soon.