Chest, back and shoulder pain on left side occurred  on day 2 after vaccination caused by Atelectasis of the lungs as detected on CT scan.; Chest, back and shoulder pain on left side occurred  on day 2 after vaccination caused by Atelectasis of the lungs as detected on CT scan.; Chest, back and shoulder pain on left side occurred  on day 2 after vaccination caused by Atelectasis of the lungs as detected on CT scan.; Chest, back and shoulder pain on left side occurred  on day 2 after vaccination caused by Atelectasis of the lungs as detected on CT scan.; patient received full primary immunization series of MODERNA and a third/booster dose of BNT162B2; patient received full primary immunization series of MODERNA and a third/booster dose of BNT162B2; Booster; This is a spontaneous report received from a non-contactable reporter (consumer). The reporter is the patient.  A 55 year-old female patient received BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, Solution for injection), administered in arm left, administration date 02Dec2021 (Lot number: FH0027) at the age of 55 years as dose 3 (booster), single for COVID-19 immunization. Relevant medical history included: "Chronic Joint pain caused Autoimmune Disease" (unspecified if ongoing); "non-steroidal anti-inflammatory drug (NSAID) allergy" (unspecified if ongoing), notes: known allergies: all NSAIDs. Concomitant medications included: omeprazole (PRILOSEC) and nortriptyline hydrochloride (PAMELOR). Vaccination history included: Moderna (dose 1, single, Batch/Lot No: 003B21A, Location of injection: Right Arm), administration date: 26Mar2021 at 04:00 PM, when the patient was 55 years old, for COVID-19 immunization and Moderna (dose 2, single, Batch/Lot No: 008C21A, Location of injection: Right Arm), administration date: 23Apr2021 at 12:00 PM, when the patient was 55 years old, for COVID-19 immunization. The following information was reported: OFF LABEL USE (non-serious) and INTERCHANGE OF VACCINE PRODUCTS (non-serious) both with onset 02Dec2021, outcome "unknown" and both described as "patient received full primary immunization series of MODERNA and a third/booster dose of BNT162B2;" IMMUNISATION (non-serious) with onset 02Dec2021, outcome "unknown," described as "Booster;" ATELECTASIS (non-serious), CHEST PAIN (non-serious), BACK PAIN (non-serious), and ARTHRALGIA (non-serious) all with onset 04Dec2021 at 17:00, outcome "unknown" and all described as "Chest, back and shoulder pain on left side occurred  on day 2 after vaccination caused by atelectasis of the lungs as detected on CT scan." The event "chest, back and shoulder pain on left side occurred on day 2 after vaccination caused by atelectasis of the lungs as detected on CT scan" was evaluated at the emergency room visit. Relevant laboratory tests and procedures are available in the appropriate section. Therapeutic measures were taken as a result of atelectasis, chest pain, back pain, and arthralgia, which included morphine for pain.  Additional information: The vaccination facility type was the pharmacy/drug store. The patient had no other vaccine in four weeks. The patient had no COVID-19 prior vaccination. The patient was tested for COVID-19 post vaccination via nasal swab with polymerase chain reaction (PCR) and antigen: negative on 02Sep2021.  No follow-up attempts are possible. No further information is expected.