Emergency: Pt. is a previously healthy 16-year-old presenting from an outside hospital with chest pain and troponin leak.  Pt. was in his usual state of health until Wednesday morning when he got his Covid booster shot. 12 hours after his booster shot he did begin having symptoms of subjective fever with a T-max of 99.6, chills, rigors. This lasted for about 24 hours. He then went to sleep on Thursday night and when he woke up on Friday morning he no longer had those symptoms but did have mild 1 out of 10 chest pain located over his left chest. Other than the Covid booster, he had no notable events that brought the chest pain on including trauma, exertion through sports, heavy lifting. The pain did not radiate anywhere including his back, arms, or jaw. He describes the pain as tightness. In terms of severity, he rates his pain as a 3 out of 10 at its worst with exertion and is currently at a 1.5 out of 10 while at rest. He did try taking ibuprofen which did help the pain but then it returned after few hours. Nothing else seem to help. Other than exertion, he found that taking deep breaths in worsen the pain. He also has the sensation of worsening pain with leaning forward. No changes with other positions. After the pain returned he and mom presented to ER where initial laboratory work-up with was unremarkable. He did have a troponin of 79 and repeat troponin level 1 hour later was 146. He had a normal chest x-ray and an EKG that was read as normal sinus rhythm without any ST elevations or ST depressions, but with some evidence of left atrial enlargement. He did not have a Covid test at the outside hospital but mom did administer a rapid test at home which was negative. He has been going to in person school but does not have any known sick contacts at home or school. No shortness of breath, leg swelling, diaphoresis. No abdominal pain, nausea, vomiting. No URI symptoms. No changes in urine or stool output. Taking good p.o. at baseline. No fevers.   He is otherwise healthy except for seasonal allergies without any medications, no known drug allergies, no surgeries. No prior Covid infection. No cardiac history. No family history of any cardiac problem or sudden cardiac death.  Cardiology:  In summary, Pt. is a 16 year old boy with a history of chest pain beginning one day after his COVID booster and with mildly elevated troponin at an outside hospital that was very mildly elevated in our ER (0.04) and is a bit lower today, although still in the range c/w very mild injury.  His CRP is at the upper limit of normal, and his labs are otherwise unremarkable.   We will obtain a cardiac MRI to look at characteristics of his myocardium, including edema and late gadolinium enhancement.  For now, he should refrain from competitive sports, but he does not need any cardiac medications.    1/3/2022: Cardiac MRI: ? Normal valvular function. ? Normal right ventricular size and global systolic function. ? Normal left ventricular size and global systolic function. ? Possible small faint area of left ventricular late gadolinium enhancement.Faint subepicardial enhancement is noted at the basal inferior wall of the left ventricle. This findings is subtle and somewhat difficult to differentiate from background noise. ? No signs of myocardial edema or diffuse fibrosis. ? No pericardial thickening or pericardial effusion. Of note, Pt. still has little twinges of mild pain occasionally that come/go and still has that awareness feeling of his heart that is hard for him to describe. He also c/o it feeling a bit harder and different to play his trumpet yesterday. He is worried about being active as he felt more with walking over to a friends house in the neighborhood. Dr  met with pt. and his mother via call to discuss these results and his symptoms. His symptoms, elevated troponin and possible faint LGE would be considered consistent with post vaccine myocarditis/pericarditis (mild).  His current symptoms are a bit unusual and may also be related to reflux. Dr recommended that he try famotidine to see if it helps. We recommended he return in one month for another evaluation with an EKG and tentative echo. In addition, we recommended that he refrain from competitive or aerobic activities for the next 3 months at which time we will likely repeat a MRI and perform a stress test prior to clearing him.