feeling a click right before her fast heartbeat then drink water and slows it down/something clicks in body, heart beats really fast; really bad pain in her right knee; muscles really tight; didn't feel so good; she was scared to death, her nerves; anxiety; very frightened; This is a spontaneous report from a contactable consumer (patient). A 78-years-old female patient received bnt162b2 (PFIZER- BIONTECH COVID- 19 VACCINE, Solution for injection), via an unspecified route of administration, administered in arm right on 21Jan2021 (at the age of 78-year-old) (Batch/Lot Number: EL1283) as 1st dose, single for covid-19 immunisation. Medical history included hypo thyroiditis (does not have it anymore, it was 30 years ago when she was a teacher), knee that was broken twice and allergic to antibiotics from an unknown date and unknown if ongoing. The patient's concomitant medications were not reported. On an unspecified date, the patient experienced feeling a click right before her fast heartbeat then drink water and slows it down/something clicks in body, heart beats really fast, really bad pain in her right knee, muscles really tight, didn't feel so good, she was scared to death, her nerves, anxiety and very frightened. The reporter stated that feeling a click right before her fast heartbeat then drink water and slows it down, was happened after she got her first covid shot. The patient asked to know if it was safe for her to get the second dose of the vaccine. The patient wondered if anyone else, she had the first Pfizer vaccine, later clarified as the COVID vaccine, a week ago last day before the time of this report, and she used to have a really fast heartbeat, but it slowed down, and once in a while, it was fast and stuff, now she had this happened twice, where she felt something click in her body, her heart beats really fast, and she drank water immediately, it slows down, has anyone said this after getting the vaccine. She has been on the phone for two hours. She never had a little click, she had thyroid hypo thyroiditis and every evening she would have a fast heartbeat, her blood pressure would go, but she never had when she would feel this little click, like a little, and her heart was really fast in morning of the report, it was really fast, and the minute she drinks water, it slows it down, it does not make sense. Also, her muscles are really tight, she was 78 and having a hard time with this pandemic, her nerves not good, she was nervous about the vaccine. She stated she was a teacher, and her weight was 106-107 pounds. About the event feeling a click right before her fast heartbeat then drink water and slows it down/something clicks in body, heart beats really fast, the patient stated, unknown when this started, exact date unknown, this has happened twice, this morning was the second one, and the minute she drank water, it slows it down, but it was very very fast, and she did not feel so good after, she was scared to death, her nerves are shot, she has trouble with anxiety, she was feeling ok now. She was nervous about what was going on and would feel better if someone else said they experienced the same. About the event muscles being really tight, the patient stated she has knots, her muscles are tight in her shoulders and neck lots, last night she was writing recipes, she does recipes boxes for her grandkids, and she was using her right arm a lot, she does not get to go to spa since the pandemic, she has not gotten to go to her for over a year. Her husband rubbed it out, and she did heat. Her muscles were tight right after she did it, so it could be something, it said if you think you had a symptom and also the second night after, she had a really bad pain in her right knee, it lasted one night, it was a knee that was broken twice, which may be why it was that leg. She was very very frightened to take it, she reacts to things strangely, when she has any procedure, they always say they never had that happen to anyone, she was allergic to antibiotics, different things happen when she takes different things, she was nervous about the whole thing, which may have to do with it. The second dose is on 12Feb2021. The outcome of the event muscles really tight was recovering and unknown for other events.  Follow-up attempts are completed. No further information is expected.