Cases of myocarditis or pericarditis (inflammation of the heart) have been reported very rarely after COVID-19 vaccines. Most of these cases have been in younger men. Most of these people recovered and felt better following rest and simple treatments. COVID-19 infection can also lead to myocarditis or pericarditis.
You should get medical advice urgently if, after your vaccination, you have:
chest pain
shortness of breath, or
a fast-beating, fluttering or pounding heart.
If you do feel unwell it is important to get advice from a doctor or nurse. Make sure you tell them about your vaccination (show them your vaccination card, if possible) so that they can assess you properly.
In the UK the safety of medicines, including vaccines, is monitored by the MHRA.