left arm also started swelling, it slowly swelled over time; It did pain her sometimes because it was heavier than her right arm but it did not pain her, all the time, it's sore.; It did pain her sometimes because it was heavier than her right arm but it did not pain her, all the time, it's sore.; This is a spontaneous report from a contactable consumer (patient). A 75-year-old female patient received second dose of BNT162B2 (Pfizer product), lot number EM9810 with expiration date 30Jun2021, via an unspecified route of administration in the left arm on 19Feb2021 as single dose for COVID-19 immunization. The patient previously received the first dose on 26Jan2021 and experienced egg-shaped raised area on the left arm/recalled it being hard on Jan2021 to unspecified date in 2021 (lot number EL3247 with expiration date 31May2021). Facility of vaccine administration: major hospital. Medical history included diabetic type 2, a lot of allergies to different drugs, allergies: she can't take penicillin, she was allergic to a lot of antibiotics, and sulfa. That's about all. Concomitant medication included apixaban (ELIQUIS; lot number 1817734 with expiration date Jan2024) as blood thinners. The patient received the first dose of the Pfizer Covid-19 vaccine on 26Jan2021 and the second dose on 19Feb2021. Both doses were administered in the left arm. After the first (reported as second; discrepancy) dose of the Pfizer Covid-19 vaccine, the patient experienced an egg-shaped hard bump and swelling. She was asking if swelling is a side effect of the Pfizer Covid-19 vaccine. She wanted to get the booster dose of the Pfizer Covid-19 vaccine and was asking if it should be given in the right arm due to the side effects she experienced in her left arm after the first dose. After her first shot, she got both shots in the left arm, she got this thing that was kind of an egg-shaped hard bump on her arm, it was big. After both shots in Mar2021, the left arm also started swelling, it slowly swelled over time. She has had 5 different procedures done and they didn't know what's wrong with her arm, she had to learn to live with it. The first 3 doctors she saw said it has nothing to do with the Pfizer shot. The last doctor that she saw which was like a vein specialist said that because they didn't know enough about the shot, it could be from that. She stated that now she cannot get blouses, they have to be tapered on left arm because it was so big. They were fitting her for a compression sleeve and that was all they can do with it. She was pretty sure it had to do with the Pfizer shot. She had a lot of allergies to different drugs. Since after this happening with the Pfizer shot, she would still get the shot even if she knew this was going to happen. Now she had to buy different clothes. It did pain her sometimes because it was heavier than her right arm but it did not pain her, all the time, it's sore in 2021. She obtained her covid vaccine card. She knew she got it in Mar2021 but on the card it said the first dose as 26Jan2021 and the second dose as 19Feb2021. She went to the hospital to receive the vaccine, she didn't know why they had the date mixed up. She later confirmed vaccine dose dates on her covid card were correct and she had mistaken it for being sometime in Mar2021. Her primary care doctor knew about her arm. The egg-shaped raised area came the day after, the swelling she didn't notice because it was so slow, she recalled that she went to family doctor in May2021 and by then it was swelled up, the doctor didn't think it was important. The egg-shaped area started at the end of Jan2021. She didn't know when but it slowly went away. She recalled it being hard. She knew the swelling was present in May2021 but she didn't know when it started. It has just gotten bigger over the month, she thinks it stopped growing but it's not going down, it's just the same right now. She was diabetic type 2. She was taking blood thinners but she didn't think she was asking the blood thinner when she got the shots , it's called Eliquis she thinks it was prescribed after the covid vaccine but was not positive Eliquis (Lot 1817734 and Exp Jan2024). Investigation: In Jun2021 or Jul2021, she took a test to see if had a blood clots and that was negative. In Jul2021, she had a CT scan of her whole shoulder and it showed nothing. In Aug2021, she went to the vein specialist in which they put liquid in the vein to see if there was a clog and that was negative. All 3 procedures were negative. Treatment: There was nothing she can do about it. She did all the tests and nothing was wrong. The last thing she was fitted for was a compression sleeve, she was being fitted for it now. She has had to see physicians but has not had to go to the emergency room. Prior to ending the call, she asked that she would like to get the booster shot, should she get it in the same arm or in the right. The outcome of events was not recovered.  Follow-up attempts are completed. No further information is expected.