It feels just like the time I had fluid around my heart. I think that's what this is; I'm having massive pain in my joints; Nausea; I'm thinking I had a heart attack; I felt like I can't catch my breath; Constant pain in my chest/I'm having constant pain in my chest.; This spontaneous case was reported by a consumer and describes the occurrence of CHEST PAIN (Constant pain in my chest/I'm having constant pain in my chest.), FEELING ABNORMAL (It feels just like the time I had fluid around my heart. I think that's what this is), MYOCARDIAL INFARCTION (I'm thinking I had a heart attack) and DYSPNOEA (I felt like I can't catch my breath) in a male patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Heart attack (had a heart attack 2 yrs ago) and Pericarditis (Pericarditis about 10 to 12 yrs ago.).    In November 2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 03-Dec-2021, the patient experienced CHEST PAIN (Constant pain in my chest/I'm having constant pain in my chest.) (seriousness criterion medically significant), MYOCARDIAL INFARCTION (I'm thinking I had a heart attack) (seriousness criterion medically significant), DYSPNOEA (I felt like I can't catch my breath) (seriousness criterion medically significant) and NAUSEA (Nausea). On 08-Dec-2021, the patient experienced FEELING ABNORMAL (It feels just like the time I had fluid around my heart. I think that's what this is) (seriousness criterion medically significant) and ARTHRALGIA (I'm having massive pain in my joints). At the time of the report, CHEST PAIN (Constant pain in my chest/I'm having constant pain in my chest.), FEELING ABNORMAL (It feels just like the time I had fluid around my heart. I think that's what this is), MYOCARDIAL INFARCTION (I'm thinking I had a heart attack), DYSPNOEA (I felt like I can't catch my breath), ARTHRALGIA (I'm having massive pain in my joints) and NAUSEA (Nausea) outcome was unknown.            Patient had a heart attack 2 years ago and  Pericarditis  10 to 12 years ago. Concomitant medications were not reported.  Patient had Moderna Covid-19 vaccine booster dose on 28Nov2021 or 29Nov2021 . On 03Dec 2021, Patient thought he had heart attack, he had nausea, constant pain in his chest and felt like he could not catch his breath. On 08 Dec 2021, patient felt like the time he had fluid around my heart, he reported having massive pain in his joints and constant pain in his chest.  I really don't want to go to the doctor. I just don't want to start racking up huge hospital bills. No treatment information was provided by the reporter.   Company comment: This spontaneous case concerns a male patient of unknown age with a relevant medical history of Myocardial infarction and Pericarditis, who experienced the  unexpected serious (medically significant) events of Chest pain, Dyspnoea and suspected Myocardial infarction and the expected serious (medically significant) event of suspected Pericarditis after mRNA- 1273 Moderna vaccine. The onset of the events occurred approximately 4 days after the booster dose of mRNA- 1273 vaccine. Clinical manifestations included nausea, chest pain, dyspnoea and subsequently the patient also developed Arthralgia. Initially, the patient thought he was having a heart attack, but he later on suspected Pericarditis. However, medical consultation we not performed. Prior history of Myocardial infarction and Pericarditis remain a confounder. The benefit-risk relationship of mRNA- 1273 vaccine is not affected by this report.; Sender's Comments: Company comment: This spontaneous case concerns a male patient of unknown age with a relevant medical history of Myocardial infarction and Pericarditis, who experienced the  unexpected serious (medically significant) events of Chest pain, Dyspnoea and suspected Myocardial infarction and the expected serious (medically significant) event of suspected Pericarditis after mRNA- 1273 Moderna vaccine. The onset of the events occurred approximately 4 days after the booster dose of mRNA- 1273 vaccine. Clinical manifestations included nausea, chest pain, dyspnoea and subsequently the patient also developed Arthralgia. Initially, the patient thought he was having a heart attack, but he later on suspected Pericarditis. However, medical consultation we not performed. Prior history of Myocardial infarction and Pericarditis remain a confounder. The benefit-risk relationship of mRNA- 1273 vaccine is not affected by this report.