acid reflux; unnecessary belching/burping; Fever; pain in body; headache; This is a spontaneous report from a contactable consumer (patient). A 37-year-old male patient received bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE, Solution for injection, Batch/Lot number was not reported, Expiry date: unknown), dose 1 via an unspecified route of administration, administered in arm left on May2021 as dose 1, single, dose 2 via an unspecified route of administration, administered in arm right on 12Jun2021 (Batch/Lot number was not reported, Expiry date: unknown) as dose 2, single for covid-19 immunisation. The patient medical history was not reported. Concomitant medications was none. The patient experienced acid reflux, unnecessary belching/burping on 29May2021, fever, pain in body, headache on an unspecified date. Caller is calling to report issues he had been facing after his two COVID shots. The main concern started when he got the first shot. He felt some sensation in the middle of his throat to his tummy line to the middle of his chest. It happens when he lays down to sleep. The sensation of air flowing inside the middle of his chest. He has read online some people report the same thing . It is acid reflux. He went to the doctor, and she did an x-ray of his chest and it came back fine. She also did an ultrasound for his thyroid. Both were fine. He has had no other issue. His doctor gave him an antibiotic from 03Jun2021. He took it for 5 days and stopped because he thought he was fine. Two days later it started again so he finished the 10 day treatment. It was prescribed to mitigate any issue he was having. This problem still occurs every 3-4 days. It happens mostly when he lays down on his left side mostly. It starts again. This has happened since the first shot. He had no other adverse effect after the first one. After the second he did have a fever and pain in his body. It went away the second day. By the third day he had no side effects. Caller did take Tylenol for the fever and pain. The second day after the second vaccine, he also had a small headache that went away. The third day, he was absolutely fine. The acid reflux has been going on more than a month now. He got the vaccine. He has told his doctor. He did join the gym after the first vaccine, and the soreness was gone at that time. At first though he thought maybe it was due to chest exercises he was doing. The soreness from the gym went away. He started researching, and saw that other people had this issue after the vaccine. The first time he noticed the acid reflux was 29May2021. He had slept on his left side, and he felt like something was running up and down in his chest. He also had unnecessary belching/burping that he didn't have before. The first day was worse because he couldn't sleep. After the antibiotic he did feel better. He slept fine. Yesterday night, it was triggered again with high intensity. But now he is absolutely fine. He does go to the gym. He doesn't feel pain in his chest. The only thing was his throat lining from his neck to his stomach seems to have a sensation in between. He got the first shot in his left arm, and the second in his right. He doesn't remember the dates. He doesn't have the NDC/lot/expiration of the two vaccines. He knows the second vaccine was 12Jun2021. The first vaccine was the last week of May2021. His doctor gave him an antibiotic from 03Jun2021. He took it for 5 days and stopped because he thought he was fine. Two days later it started again so he finished the 10 day treatment. He doesn't know the name of the antibiotic of any details. NDC/lot/expiration not provided. It was prescribed to mitigate any issue he was having. This problem still occurs every 3-4 days. The patient underwent lab tests and procedures which included chest x-ray: normal and ultrasound thyroid: normal on an unspecified date. The outcome of event acid reflux and unnecessary belching/burping was not recovered, rest of the events was recovered.  Information on the lot/batch number has been requested. Additional information is requested.