Big arthritis flare in hands/Right shoulder now inflamed; Within 2 weeks, I began feeling pain in Left forearm muscle; Which migrated up to upper arm, and then appeared in right arm and took the same course, now fully in both arms. Pain when still or in motion, especially in motion.; Can't lift arm without pain; Inappropriate schedule of vaccine administered; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 73-year-old female patient received BNT162b2, BNT162b2 omi ba.4-5 (BNT162B2, BNT162B2 OMI BA.4-5), on 28Dec2022 at 10:15 as dose 6 (booster), single (Lot number: GLO446) at the age of 73 years, in left arm for covid-19 immunisation. The patient's relevant medical history included: "Atrial fibrillation" (unspecified if ongoing); "COVID-19" (unspecified if ongoing). Concomitant medication(s) included: PARNATE; APIXABAN. Vaccination history included: moderna coviD-19 vaccine, bivalent (Dose 5 (Booster), Single, Batch/lot number: 059F22A, Anatomical Location: Arm Left), administration date: 04Nov2022, for COVID-19 immunisation; Covid-19 vaccine (Dose 1, Manufacturer Unknown), for COVID-19 immunisation; Covid-19 vaccine (Dose 2, Manufacturer Unknown), for COVID-19 immunisation; Covid-19 vaccine (Dose 3 (Booster), Manufacturer Unknown), for COVID-19 immunisation; Covid-19 vaccine (Dose 4 (Booster), Manufacturer Unknown), for COVID-19 immunisation. The following information was reported: INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (non-serious) with onset 28Dec2022, outcome "unknown", described as "Inappropriate schedule of vaccine administered"; ARTHRITIS (non-serious) with onset 09Jan2023, outcome "not recovered", described as "Big arthritis flare in hands/Right shoulder now inflamed"; PAIN (non-serious) with onset 09Jan2023, outcome "not recovered", described as "Can't lift arm without pain"; PAIN IN EXTREMITY (non-serious) with onset 09Jan2023, outcome "not recovered", described as "Which migrated up to upper arm, and then appeared in right arm and took the same course, now fully in both arms. Pain when still or in motion, especially in motion."; MYALGIA (non-serious) with onset 09Jan2023, outcome "not recovered", described as "Within 2 weeks, I began feeling pain in Left forearm muscle". The events "big arthritis flare in hands/right shoulder now inflamed", "within 2 weeks, i began feeling pain in left forearm muscle", "which migrated up to upper arm, and then appeared in right arm and took the same course, now fully in both arms. pain when still or in motion, especially in motion." and "can't lift arm without pain" required physician office visit. Relevant laboratory tests and procedures are available in the appropriate section. Therapeutic measures were not taken as a result of arthritis, myalgia, pain in extremity, pain.  Additional information: Adverse event: Within 2 weeks, Patient began feeling pain in Left forearm muscle, which migrated up to upper arm, and then appeared in right arm and took the same course, now fully in both arms. Can't lift without pain, also big arthritis flare in hands, right shoulder now inflamed. Seems to be in muscle fascia. Never experienced before. Pain when still or in motion, especially in motion. Adverse event resulted in: Doctor or other healthcare professional office clinic visit. If treatment Adverse event: No. If COVID prior vaccination: Yes. If COVID tested post vaccination: Yes.