Myocarditis burning?

28 year old male 183cm, 83kg So back in October I was diagnosed with pericarditis (later corrected to myopericarditis) The symptoms were gradually improving after a course of colchicine but following a stressful life event they began flaring up again. Last week I had a contast MRI which confirmed the myopericarditis diagnosis but suggested that my heart's recovering & didn't really explain why i'd still be feeling pain Long story short I will be going back on the colchicine and if my symptoms don't improve will be undergoing a lung function test due to shortness of breath symptoms. Fast forward to yesterday and all of a sudden I have a completely new symptom; my heart area started feeling like it was on fire. Ive never had heartburn in my life & since then I've had 3 episodes which (given my eating times) I dont believe can be down to acid reflux. I've just taken a walk to lunch and for the first time ever it seems painful to walk? My heart pain has never had any correlation with activity but now the pain definitely spiked when I started moving. The pain is also nothing like I had before; it was previously more like a sharp, pinching pain but now it's more blunt, like im being punched