got red and hard; bump under right armpit; bump at injection site, arm got real stiff; she felt lots of pain under both armpits; Caller states that on Friday she got the Pfizer booster vaccine and she originally had taken her first and second shot of the Moderna brand; Caller states that on Friday she got the Pfizer booster vaccine and she originally had taken her first and second shot of the Moderna brand; Caller states that on Friday she got the Pfizer booster vaccine; bump at injection site, arm got real stiff; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 52 year-old female patient received bnt162b2 (BNT162B2), administered in arm right, administration date 03Dec2021 (Lot number: 33136BA) at the age of 52 years as dose 3 (booster), single for covid-19 immunisation. Relevant medical history included: "allergic person" (unspecified if ongoing), notes: she is an allergic person; "reacts easily to different medication" (unspecified if ongoing), notes: reacts easily to different medication. The patient took concomitant medications. Vaccination history included: Moderna vaccine (First Dose, Moderna vaccine, administered on 23Apr2021, LOT-004C2JA), administration date: 23Apr2021, when the patient was 51 years old, for COVID-19 immunization; Moderna vaccine (Second Dose, Moderna vaccine, administered on 11Jun2021, LOT-053C2IA), administration date: 11Jun2021, when the patient was 51 years old, for COVID-19 immunization. The following information was reported: OFF LABEL USE (non-serious), INTERCHANGE OF VACCINE PRODUCTS (non-serious) all with onset 03Dec2021, outcome "unknown" and all described as "Caller states that on Friday she got the Pfizer booster vaccine and she originally had taken her first and second shot of the Moderna brand"; IMMUNISATION (non-serious) with onset 03Dec2021, outcome "unknown", described as "Caller states that on Friday she got the Pfizer booster vaccine"; VACCINATION SITE MASS (non-serious), MUSCULOSKELETAL STIFFNESS (non-serious) all with onset 03Dec2021, outcome "not recovered" and all described as "bump at injection site, arm got real stiff"; AXILLARY MASS (non-serious) with onset 04Dec2021, outcome "not recovered", described as "bump under right armpit"; ERYTHEMA (non-serious) with onset 05Dec2021, outcome "recovering", described as "got red and hard"; AXILLARY PAIN (non-serious) with onset 03Dec2021, outcome "unknown", described as "she felt lots of pain under both armpits". The events "bump at injection site, arm got real stiff", "bump under right armpit", "got red and hard", "bump at injection site, arm got real stiff" and "she felt lots of pain under both armpits" were evaluated at the physician office visit. Therapeutic measures were not taken as a result of vaccination site mass, axillary mass, erythema, musculoskeletal stiffness, axillary pain.  Additional Information: Patient got booster shot on Friday 03Dec2021, around mid morning, exact time unknown. Patient is an allergic person, is under treatments for allergies, reacts easily to different medication, history of being sensitive. Patient states that immediately she started feeling her arm that it was hard and it was a bump right around the area she received the shot, states thought that was just a normal, states her arm got real stiff, thought that was also normal, states overnight she felt lots of pain under both armpits, stated that the following day on Saturday morning and touched her armpit and felt a bump, about the size of a mandarin under her right arm. States it was worse on Sunday, got red and hard, today it is less but it is going down slowly, and it still hurts. Patient states she went to the doctors office to check her symptoms, no treatment, told her it was a reaction and told her to use hot compresses and it would go away with time.  No follow-up attempts are possible. No further information is expected.