I can't sleep; in a 10/10 pain; I can't lift my arm; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team, Program ID. The reporter is the patient.  A 75-year-old female patient received BNT162b2 (COMIRNATY), on 15Oct2021 as dose 3 (booster), single (Lot number: 3015JBA) at the age of 74 years, in right arm for covid-19 immunisation. The patient's relevant medical history included: "Cancer", start date: 1977 (ongoing), notes: Cancer diagnosed many years ago in 1977; "memory problem" (ongoing), notes: memory problem states began before the Pfizer, COVID vaccine and she fell in #. The patient's concomitant medications were not reported. Vaccination history included: Bnt162b2 (Dose 1), for Covid-19 Immunization; Bnt162b2 (Dose 2), for Covid-19 Immunization, reaction(s): "had pain but it was nothing big". The following information was reported: MUSCULAR WEAKNESS (non-serious) with onset 15Oct2021, outcome "unknown", described as "I can't lift my arm"; PAIN (non-serious) with onset 15Oct2021, outcome "not recovered", described as "in a 10/10 pain"; INSOMNIA (non-serious) with onset 18Oct2021, outcome "unknown", described as "I can't sleep". The event "i can't lift my arm" required physician office visit. The event "in a 10/10 pain" required emergency room visit. Relevant laboratory tests and procedures are available in the appropriate section. Therapeutic measures were taken as a result of muscular weakness, pain.  Additional information: Patient states that her Pfizer COVID vaccine booster dose was 6 months ago on Friday and she had the booster dose on 15Oct2021 and got the Pfizer 1st and 2nd COVID vaccines at withheld and had no problems or a little problem with the 2nd dose of the vaccine but no more than a flu shot kind of thing and when the booster came around the #, they chose not to give them the booster dose but contracted with # and she got her booster dose there. Patient States she has had problems with it and has been in pain since that day when she got the booster dose on 15Oct2021; states her right arm has pain and she can only lift her arm a little bit and cannot lift it much and so she has been going to physical therapy but they told her last week that physical therapy is not making any difference and she is still in pain; states physical therapy is not working. Physical therapy is doing a great job there and she is happy with them and they have been working on her for months and last week they said they do not know what else to do for her and took all the notes and are sending them to her doctor that she will see on 04May2022 and she does not know what to do. Patient thinks the batch number she gave for the Pfizer Booster dose of the COVID vaccine had a B on the end of the number; caller states she has no lots, expiry dates or NDC numbers to provide for her 1st, 2nd or booster doses of the Pfizer COVID vaccine as her patient card is not with her at this time. States the Pfizer COVID vaccine booster dose was administered to her right arm which is the same side as her arm pain and she has to have all of her shots on her right arm as she is a cancer patient and they took lymph nodes out of her left arm and she has pain from that. Caller states she is convinced this reported issue is a # issue. States her pain is ongoing and might be the same and ended up with physical therapy and she is going to talk to her doctor and cancel her from physical therapy as she is not any better. States her 2nd dose of the Pfizer COVID vaccine she had pain but it was nothing big and that began just a couple of days or had a day with pain; states she fell right in the middle of the range between 1.8 days to 2.6 days for people in pain and she has had so many shots in her life and was age 26 when she was in the # and they give lots of shots and this is the only one that she has had this trouble with being in such pain. States this Friday she is going to be getting a cortisone shot. Caller states the pain after her booster dose began in her right arm almost immediately and she went to the emergency room that Monday and had the shot on Friday and was in pain and over the weekend and went to the emergency on Monday. Additional Vaccines Administered on Same Date of the Pfizer Suspect: None; States she is sure she had the flu shot around that time but had no problem with it and does not know the name of it or other information and does not know if she had the flu shot and does not remember the flu shot last year but if it was given around that time then she had it.  No follow-up attempts are possible. No further information is expected.