Temple Head Pain/ pain felt like 1000 from 1-1000 pain on the side of his head where his temples are; her son had sharp stabbing pain at the temples for 5 seconds; he felt like falling backwards; her son had bad stomach ache; felt sick; it was painful for her son to walk/couldn't even walk; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the parent.  A 9 year-old male patient received bnt162b2 (BNT162B2), administered in arm left, administration date 10Jan2022 (Lot number: FK5618) at the age of 9 years as dose 1, single for covid-19 immunisation. The patient had no relevant medical history. There were no concomitant medications. Vaccination history included: Hpv9 (Dose number unknown, LOT: MI90651), administration date: Oct2021, for immunization, reaction(s): "felt sick", "Not well", "sleepy"; Influenza (Dose number unknown, Lot: 90686), administration date: Oct2021, for immunization, reaction(s): "felt sick", "Not well", "Sleepy". The following information was reported: ABDOMINAL PAIN UPPER (non-serious) with onset 10Jan2022, outcome "recovered" (10Jan2022), described as "her son had bad stomach ache"; PAIN (non-serious) with onset 11Jan2022, outcome "recovered" (11Jan2022), described as "her son had sharp stabbing pain at the temples for 5 seconds"; ILLNESS (non-serious) with onset 10Jan2022, outcome "recovered" (10Jan2022), described as "felt sick"; GAIT DISTURBANCE (non-serious) with onset 10Jan2022, outcome "recovered" (10Jan2022), described as "it was painful for her son to walk/couldn't even walk"; FEELING ABNORMAL (non-serious) with onset 11Jan2022, outcome "recovered" (11Jan2022), described as "he felt like falling backwards"; HEADACHE (non-serious) with onset 11Jan2022 07:30, outcome "recovered" (11Jan2022), described as "Temple Head Pain/ pain felt like 1000 from 1-1000 pain on the side of his head where his temples are". Therapeutic measures were not taken as a result of abdominal pain upper, pain, illness, gait disturbance, feeling abnormal, headache.  Additional information: Caller called about her 9 year-old son with initials withheld who received his first dose of the Pfizer BioNTech COVID-19 vaccine last 10Jan2022. "On the day of the vaccine, her son had bad stomach ache and it was painful for her son to walk because of the stomach ache". "A couple of hours later, it was resolved and her son was feeling better". The next day, her son had sharp stabbing pain at the temples for 5 seconds and he felt like falling backwards which lasted for most of the day but her son was fine by the time caller picked him up. Caller asked if these were reported side effects with the Pfizer BioNTech COVID-19 vaccine. Caller's son was scheduled for his second dose of the vaccine on 31Jan2022. A review of the prescribing Information (LAB-1503-3.0 Revised: 03Jan2022) for Pfizer BioNTech COVID-19 vaccine did not find information regarding stomach ache, sharp stabbing pain at temples and feeling like falling backwards specifically. However, headache and muscle pain were reported to be possible side effects with the vaccine. Caller stated her son was 9 years old and he went to withheld and he took the First Dose of Pfizer Covid 19 Vaccine for kids and as soon as he got it, he was fine. Caller stated and then about a couple hours later, his stomach started hurting really bad and then an hour or two later he was fine. Caller stated then 2 days after his head was hurting to the point, he was standing there grabbing his head and started screaming lasting 5 sec. Caller stated he was in front of her and grabbed both of his temples and then it stopped and she said are you okay and he explained he had a severe pain on both temples then he felt like as if he was falling back. Caller stated it went away but it lingered a little bit and he felt like he was falling back, that sensation. Caller stated he had his second dose on 31Jan2022. Height and Weight were unknown. Stomach Pain AE: Caller stated her son's stomach started hurting really bad 3 hours after the shot to the point where he couldn't even walk, well he thought he couldn't walk. Caller stated at first they felt fine and he was off school so they thought they would go to the mall and go to grandma's because he was feeling fine. Caller stated then all of a sudden he sat on the floor and said he felt sick and he was walking very slow and her husband had to carry him to the car, his stomach was too painful and the motion of walking hurt. Caller stated her son got in the car and they started driving to the house and by the time they got home, he slowly started feeling better, and by that evening he was running around and he was fine. Temple Head Pain AE: Caller stated her son was in her room and he had long hair to his shoulders and it was curly and she was about to style it for school so it was in the morning around 07:30 a.m. Caller stated her son was grabbing the brush and he screamed and grabbed both temples and she was horrified and he wasn't paying attention and he was in his own world for 5 seconds and that was long. Caller stated she had an oh crap moment. Caller stated it lasted 5 seconds and then he let go and said mom and explained to her the pain felt like 1000 from 1-1000 pain on the side of his head where his temples were and he felt like when he falls back that sensation. Caller stated so she told him to sit down and she asked if he was going to be okay? Caller stated he was quiet and focused and told her to be quiet. Caller stated 10 minutes later she asked him if he was going to school, and he said he will go to school because he doesn't like to miss school. Caller stated the feeling lingered throughout the day and when she picked him up, he was fine. No treatment provided and caller stated unless he was dying she doesn't like to give anything. No prior Vaccinations (within 4 weeks). Caller stated the patient had the HPV9 LOT: MI90651 vaccine last year in Oct2021 and they gave him the Influenza Lot: 90686 Shot the same date and when he got home he felt sick and sleepy and not well for 3 days. NDC and Expiration: Unknown. No family medical history Relevant to AE.  Follow-up attempts are completed. No further information is expected.