always gets "hardness at injection site" on her left arm/other than the typical soreness at the injection site; heart starts raising and beating extremely rapidly that lasted a minute and a half; fluttering in my heart; I was very tired; This is a spontaneous report received from a contactable reporter (Consumer or other non HCP) from medical information team. The reporter is the patient.  A 66-year-old female patient received BNT162b2 (BNT162B2), on 05Apr2022 as dose 4 (booster), single (Lot number: FP4554) at the age of 66 years, in left arm for covid-19 immunisation. The patient's relevant medical history included: "Blood pressure" (unspecified if ongoing); "Cold sores" (unspecified if ongoing); "Cholesterol" (unspecified if ongoing); "Allergies: Penicillin" (unspecified if ongoing); "Allergies: Sulphur drugs" (unspecified if ongoing). Concomitant medication(s) included: METOPROLOL SUCCINATE taken for blood pressure measurement; ACYCLOVIR [ACICLOVIR] taken for oral herpes; SIMVASTATIN taken for blood cholesterol. Vaccination history included: Covid-19 vaccine (Primary Immunization series complete; unknown manufacturer), for Covid-19 Immunization; Covid-19 vaccine (1st Booster, unknown manufacturer), for Covid-19 Immunization. The following information was reported: VACCINATION SITE PAIN (non-serious) with onset 06Apr2022, outcome "unknown", described as "always gets "hardness at injection site" on her left arm/other than the typical soreness at the injection site "; ATRIAL FLUTTER (non-serious) with onset 06Apr2022, outcome "unknown", described as "fluttering in my heart"; HEART RATE INCREASED (non-serious) with onset 06Apr2022, outcome "recovered" (06Apr2022), described as "heart starts raising and beating extremely rapidly that lasted a minute and a half"; FATIGUE (non-serious) with onset 06Apr2022, outcome "unknown", described as "I was very tired". Relevant laboratory tests and procedures are available in the appropriate section. Therapeutic measures were taken as a result of vaccination site pain.  Additional information: Caller states she just received her Pfizer Covid-19 second booster shot last Tuesday 05Apr2022. Caller states she never had any issues before with the vaccine and is calling to report a potential side effect. Caller states she always gets hardness at injection site on her left arm and it goes away. Last night when she was about to sleep, she turned on her side then her heart starts raising and beating extremely rapidly that lasted a minute and a half. No chest pain and shortness of breath. Caller states when she rolled over slowly it did dissipate. Caller states she never had that prior to getting the booster shot. Caller states she didn't know if it is a reaction or can be related to myocarditis. Consumer stated, "I had my second COVID booster, the Pfizer booster on Tuesday afternoon this week and I felt fine other than the typical soreness at the injection site and last night when I just turned out the light to go to sleep and I rolled over to my side, I had the injection on my left arm and then all of a sudden, I felt this sudden surge, like fluttering in my heart and it seemed to go on for about a minute or a minute and a half. The point it was fluttering hard enough that I kind of put my right hand over my heart and I could feel my heart beating very rapidly and I rolled over on my back and I just took slow, kind of steady breath and then it kind of dissipated. I was very tired I just want to go to sleep because I thought if I go to sleep, I don't know if something is going to happen or should stay awake that something happens. But anyway, it did seem to disappear on its own and I don't know if this is a direct result of the vaccine. My age is 66 and given the (voice not clear) that was handed to me at the time of the vaccine, I don't know if I, I mean I didn't have chest pain and didn't have short-ness of breath. I just had a quick onset of my heart increasing in speed. Consumer stated that I had Pfizer all along and I never had, other than the typical sores at the injection site, I never had any reaction.  No follow-up attempts are possible. No further information is expected.