I felt like my pelvis is cracked, like my pelvic bone is cracking.; I could not walk for almost 2 days; I fell on the floor; crying; I don't know how to function, how to go to work/I was having a very bad time to get up by myself/I couldn't carry myself to the bath.; I did not go to work; I am feeling the pain; When I sneezed my back started to hurt/I had a terrible back pain; Feverish/ I was having a fever; fatigued; Hard to sit; This is a spontaneous report from a contactable consumer (patient). A 27-year-old female patient received first dose of bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Formulation: Solution for injection, Batch/Lot Number: EW0181) via an Intramuscular route of administration, administered in Arm Left on 26July2021 at 15:00 (at the age of 27 years old) as single dose for COVID-19 immunisation. Medical history include asthma from unknown date to unknow if ongoing, taking medication for Asthma and treatment with Inhaler Albuterol and Inhaler Advair. Concomitant medications were not reported. The patient did not receive any other vaccines within four weeks prior to the vaccination. The reporter said Second vaccination shot due date is on 17Aug2021. On an 27July2021 patient experienced that patient had my Pfizer vaccine last Monday, 26Jul2021 in the afternoon around 3:30, I had a bad reaction. The next day I felt fatigue, I felt feverish during the day and at night I started to have a back pain. The back pain is when I sneeze, I felt like my whole pelvic area is cracking like it was terrible that started around 8, so I was laying on the couch watching TV. When I decided to get up from the couch, I fell in the floor, and I had no strength to pick up myself from the floor then patient called friend to come to my Apartment and pick me up from the floor because I couldn't get up by myself. I was having a very bad time to get up by myself and then she came and pick me up probably around 9:30-10:00. She gave me a hot pad and I took medicine. The next day I still couldn't walk, I am crawling to my bathroom and my friend came here to help me to walk to the bathroom because I couldn't carry myself to the bath. I couldn't walk and I was crawling, and I was like crying and I was like that for more than 24 hours. The next day Thursday I was able to walk very slowly but I couldn't bend my back it was so hard to get up, I get up sideways. It's so hard to sit on the toilet on unspecified date. It's so hard to like to reach the flush and flush it because I need to bend a little bit and when she found me actually on the Tuesday night I was having a fever. Then until now I have a very bad back pain and it is still feel 9 out of 10 but the difference is I can walk but I still don't work. I didn't go to work for 3 days after the reaction because I don't know how can I go back to work with terrible back pain. We are wearing a lab gown inside the lab and its heavy and I have been really bad back pain that's never happen to me this bad, so I am in very bad pain. The patient received treatment for the events with Tylenol 1000 mg every 8 hours and Advil every 6 hours. The outcome of the events was not resolved.  Follow-up attempts are completed. No further information is expected.