her back started to hurt/a lot of back pain/increased back pain after receiving the third dose; This is a spontaneous report from a contactable consumer and in response to mail trail sent regarding the confirmation of below mentioned query. This 68-year-old female nurse (patient, reported for self). A 68-year-old female patient received third dose of bnt162b2 (PFIZER BIONTECH COVID-19 mRNA VACCINE; Solution for injection; Lot Number: FC3181), via an unspecified route of administration, administered in left arm as dose 3 (booster), single on 21Aug2021 (at the age of 68-year-old) for covid-19 immunisation. Medical history included patient had back pain since she was 27, mitral valve defect and replacement when she was 10 and insomnia (Insomniac) from an unknown date and unknown if ongoing. The patient's concomitant medications were not reported. Patient had earlier received the first dose of bnt162b2 (PFIZER BIONTECH COVID-19 mRNA VACCINE; Solution for injection; Lot Number: EV9899 or EN9899), via an unspecified route of administration, administered in left arm as dose 1, single on 20Dec2020 (at the age of 67-year-old) for covid-19 immunisation and experienced first dose she slept for like 3 days, sore arm and severe fatigue;  second dose of bnt162b2 (PFIZER BIONTECH COVID-19 mRNA VACCINE; Solution for injection; Lot Number: EL3247), via an unspecified route of administration, administered in left arm as dose 2, single on 18Jan2021 (at the age of 67-year-old) for covid-19 immunisation and experienced no side effects and also took flu shots on unspecified date(s) and experienced sore arm. Patient was a nurse and work night shift, they get a few COVID patients and so they were at risk. Reporter (patient) stated she just had her third injection of the Pfizer on 21Aug2021 (on Saturday) and she was well/fine before she didn't really have side effects the first 2 times, but this time she had a lot of back pain. On unspecified date in 2021, patient experienced increased back pain after receiving the third dose Pfizer Covid 19 Vaccine. Patient had back pain previously but it worsened lately, didn't know if it was increased pain. She stated that the back pain was normal for her but that its worse, she does not think that the back pain was related to vaccine as she has had back pain since she was 27 years old and now 68 years old. She also stated that she had a mitral valve defect and replacement when she was 10. The patient can't really say when it began after receiving the third dose Pfizer Covid 19 Vaccine, was not thinking about it until the point where the patient wanted to take something for the pain. The patient stated the back pain was a chronic condition made little worse but thought this was because she usually takes Aspirin at least twice a day for her back but hasn't been since the third dose Pfizer Covid 19 Vaccine on Saturday as she read that you weren't supposed to take it before or after. The patient was about to the point of had to take Aspirin, because the back pain was that bad. The patient stated she was not blaming the Pfizer Covid 19 Vaccine. Patient wanted to know when it would be okay for her to take Aspirin or pain medication. The patient usually, up until the Covid 19 Vaccine, just went ahead and took Aspirin when the patient's back hurt, regardless of the Pfizer Covid 19 Vaccine. The patient didn't know there could be a connection. Patient googled last night read not to take Aspirin or Tylenol, doesn't know if it will effect the Pfizer Covid Vaccine or not. Therapeutic measures were taken as a result of her back. The Pharmacist that gave her the injection said to take Tylenol or Aspirin or whatever she normally takes. Patient stated she took Aspirin because Tylenol doesn't work for her. Patient stated she was reading that Ibuprofen, Tylenol, or Aspirin shouldn't be taken after the vaccine because it might interfere. Patient stated she was wondering if that was true, it seems like it was, it was put out by news. Patient stated she thought Pfizer was doing a wonderful job and grateful for the Pfizer Covid 19 Vaccine. The event was non-serious. At the time of this report, the outcome of event was not recovered. Causality: Not necessarily, probably not.  Follow-up attempts are completed. No further information is expected.