My left hip was very sore and it got worse; My left hip was very sore and it got worse; The pain was so bad I couldn't move and I also had a lot of pain in my right shoulder; The pain was so bad I couldn't move and I also had a lot of pain in my right shoulder; I think it exacerbated, it kicks in my immune system; Pfizer shot affected my immune system and started this but this is my guess; This is a spontaneous report from a contactable consumer (patient). An 82-year-old female patient received BNT162B2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, formulation: Solution for injection, Batch/Lot Number: EM9809), via an unspecified route of administration on 26Feb2021 as 2nd dose, single for COVID-19 immunization (age at the time of vaccination was 82-year-old). The patient's medical history included blood pressure and arthritis. Concomitant medications included hydrochlorothiazide (HYDROCHLOROTHIAZIDE) taken at 12.5 mg for blood pressure. Historical vaccine included BNT162B2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, formulation: Solution for injection, Batch/Lot Number: EL9264), via an unspecified route of administration on an unspecified date as 1st dose, single for COVID-19 immunization vaccination. On an unspecified date in 2021, the patient stated after the second shot I got some side effects and a few days after it began, and it was my left hip was very sore and it got worse. The patient made an appointment with the orthopaedist but before she could get to see him, she had to go to the Hospital in the ambulance because the pain was so bad she could not move and she also had a lot of pain in my right shoulder which went on a couple of weeks, just beginning to light up a little bit that day. So, she thought it was a side effect because I thought it was exacerbated, it kicked in my immune system so that was what I was thinking it was and I just reported it. The patient stated regarding outcome as yes but it has alleviated quite a bit I mean it was very bad , quite a lot actually today anyways it's pretty good and I have been on Prednisone (treatment), I am in the middle of taking that. I started taking it (Prednisone) 10 days ago. I have another week to go on it's a reduce dose you know you take 2 a day to 5 days, when you take you take two twice a day for five days then you take one twice a day for five days and you take one a day for five days." When probed if consumer is taking any medication other than Prednisone, consumer stated, "Not for the pain, I mean I do have other medications beside Prednisone. I am taking Hydrochlorothiazide (Clarified as concomitant medication) and nothing else. "Regarding start date of event the patient stated, "I can only give you an approximation it was about maybe four or five days later approximately. I started felling sore on my hip and then it gone worse. From 02Mar would be a good guess. She was guessing that the Pfizer shot affected her immune system and started but this is my guess, I am not a doctor. Treatment medication included Prednisone for all the events expect I thought it exacerbated, it kicked in my immune system. Outcome of all the events was reported as recovering and unknown for the event I thought it exacerbated, it kicked in my immune system.  No follow up attempts are possible. No further information is expected.