She is complaining that her arm is hurting ever since.; There is a big knot though where they did the injection and it feels so hard; You can feel it, you can even see it, right below where they gave it.; There is a big knot though where they did the injection and it feels so hard; You can feel it, you can even see it, right below where they gave it.; it was really red; Her step mothers arm swelled; knot on left arm below injection site; This is a spontaneous report from a contactable consumer or other non hcp. A 82-Years-old female patient received BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, formulation: Solution for injection, Lot Number: EL3247), via an unspecified route of administration, administered in Arm Left on 02Feb2021 (at the age of 82-Years-old) as dose number unknown, single for COVID-19 immunisation. Medical history included arthritis from an unknown start and stop date. The patient's concomitant medications were not reported. Patient experienced She is complaining that her arm is hurting ever since, There is a big knot though where they did the injection and it feels so hard; You can feel it, you can even see it, right below where they gave it., it was really red, Her step mothers arm swelled on an unspecified date, On 25Mar2021 knot on left arm below injection site. It was reported that it's about step-mother that I am calling about. Reporter stated, "I took my step-mom when I went to get my shot and my brother went with us and the 2nd shot was February the 2nd and she is complaining that her arm is hurting ever since and she is 83 I think. Anyway I went up to help her get shower and I just felt she is complaining, they complaining but anyway there is a big knot though where they did the injection and it feels so hard. What would cause that. When para-phrased the concern, Reporter stated, "Well she got a big knot there. You can feel it, you can even see it, right below where they gave it. Yes, that's what I want to know. "Reporter stated, "She didn't haven't get rid of the pain ever since she got the 2nd shot but you know I was told you are not supposed to take those shots in the same arm. But nobody told us that. I got mine in the same arm. She did too. I had no problem. When my husband went to get his I directed him to get in each arm but I didn't know this when I got mine. She had the 2nd shot on 02Feb2021, it started right after that and I am just calling to, it was really red to start with it was really red and it stayed red for 3, 4 weeks and now there is a knot there." Reporter stated, "I am looking at it. I have got EL3247 and then there is another real long number, I will give you that and there is something else saying on here, you want that" When probed if the patient is still experiencing the even, Reporter stated, "Yeah absolutely, that's why I called you." Her step mothers arm swelled. It was not really bad. Her arm was really bad for 4 weeks. When getting her out of the shower she felt a knot on her step mothers arm below the injection site. She does not know the answer to outcome of event. Patient did not received any treatment. The outcome of the events were reported as unknown.  No follow-up attempts are possible. No further information is expected.