costochondritis; pain in arm; chest pain; ribs 3 & 4 plus especially the right side of chest was very painful when moving; heart fluttering/fluttering/skipping heart; heart fluttering/fluttering/skipping heart; armpit pain; arm discomfort; breast pain/sore breasts that felt lumpy; breast pain/sore breasts that felt lumpy; off label use; interchange of vaccine products; this is a spontaneous report received from a contactable reporter(s) (consumer or other non hcp) from the regulatory agency. the reporter is the patient. regulatory number: gb-mhra-webcovid-202202181054560460-come0. other case identifier(s): gb-mhra-adr 26619749. a 65-year-old female patient received bnt162b2 (comirnaty), administration date 21nov2021 (lot number: fk9413) at the age of 65 years as dose 3 (booster), single for covid-19 immunisation. relevant medical history included: "breast cancer", start date: 2005 (unspecified if ongoing); "radiotherapy", start date: 2005 (unspecified if ongoing), notes: for breast cancer; "chemotherapy", start date: 2005 (unspecified if ongoing), notes: for breast cancer; "lumpectomy", start date: 2005 (unspecified if ongoing), notes: for breast cancer; "blood pressure high" (unspecified if ongoing); "indigestion" (unspecified if ongoing); "pain" (unspecified if ongoing); "stress incontinence" (unspecified if ongoing). concomitant medication(s) included: influenza virus taken for immunisation; amlodipine taken for hypertension; omeprazole taken for dyspepsia; paracetamol taken for pain; solifenacin taken for stress urinary incontinence. vaccination history included: covid-19 vaccine astrazeneca (dose 1), administration date: 24feb2021, for covid-19 vaccination; covid-19 vaccine astrazeneca (dose 2), administration date: 21may2021, for covid-19 vaccination. the following information was reported: off label use (medically significant) with onset 21nov2021, described as "off label use"; interchange of vaccine products (medically significant) with onset 21nov2021, described as "interchange of vaccine products"; costochondritis (medically significant), outcome "recovering", described as "costochondritis"; pain in extremity (medically significant), outcome "recovering", described as "pain in arm"; chest pain (medically significant), outcome "not recovered", described as "chest pain"; axillary pain (medically significant) with onset 29nov2021, outcome "recovering", described as "armpit pain"; limb discomfort (medically significant) with onset 29nov2021, outcome "recovering", described as "arm discomfort"; breast pain (medically significant), breast mass (medically significant) all with onset 21nov2021, outcome "recovering" and all described as "breast pain/sore breasts that felt lumpy"; cardiac flutter (medically significant), extrasystoles (medically significant) all with onset 26dec2021, outcome "recovered" (29dec2021) and all described as "heart fluttering/fluttering/skipping heart"; musculoskeletal chest pain (medically significant), outcome "unknown", described as "ribs 3 & 4 plus especially the right side of chest was very painful when moving". the events "costochondritis", "pain in arm", "chest pain", "armpit pain", "arm discomfort", "breast pain/sore breasts that felt lumpy", "heart fluttering/fluttering/skipping heart" and "ribs 3 & 4 plus especially the right side of chest was very painful when moving" were evaluated at the physician office visit. the patient underwent the following laboratory tests and procedures: sars-cov-2 test: no - negative covid-19 test; ultrasound scan: lymph nodes all okay. clinical course: the patient had a lumpectomy, chemotherapy and radiotherapy for breast cancer in 2005. she was on medication for 10 years subsequently. patient has not had symptoms associated with covid-19. the patient experienced very sore across chest. she couldn't bend over after having a shower to wipe it down, too painful. already had costochondritis but made it much worse. the left side was okay now but the sternum, ribs 3 & 4 plus especially the right side of the chest was very painful when moving. very painful sharp pain if cough or sneeze. lying down, sitting up or moving, or lying on my chest was very painful. where she had previously had a lumpectomy was very painful for a short time during the night a day after her vaccine. armpit pain for a couple of months. pain in arm, still aches at times and armpit aches sometimes. she had sore breasts that felt lumpy but okay now. had fluttering/skipping heart when sat down relaxing at night over the christmas period for a few days. have seen oncology and had an ultrasound scan, lymph nodes all okay. seeing a physiotherapist and had a session of ultrasound. referred to cardiology. patient has not tested positive for covid-19 since having the vaccine. patient is not enrolled in clinical trial no follow-up attempts are possible. no further information is expected