developed a bruise; my arm, stung and is sore; back pain; leg pain; feeling really achy; not feeling well; Headaches; booster; They're actually supposed to flatten the area to better reach the muscle/it bled a couple drops.; This is a spontaneous report received from a non-contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the patient.  A female patient received bnt162b2 (BNT162B2), administration date Dec2021 (Batch/Lot number: unknown) as dose 3 (booster), single for covid-19 immunisation. The patient's relevant medical history and concomitant medications were not reported. Vaccination history included: Bnt162b2 (Dose; 1), for Covid-19 Immunization; Bnt162b2 (Dose: 2), for COVID-19 immunization. The following information was reported: IMMUNISATION (non-serious) with onset Dec2021, outcome "unknown", described as "booster"; WRONG TECHNIQUE IN PRODUCT USAGE PROCESS (non-serious) with onset Dec2021, outcome "unknown", described as "They're actually supposed to flatten the area to better reach the muscle/it bled a couple drops."; CONTUSION (non-serious), outcome "unknown", described as "developed a bruise"; ARTHRALGIA (non-serious), outcome "unknown", described as "my arm, stung and is sore"; BACK PAIN (non-serious), outcome "unknown", described as "back pain"; PAIN IN EXTREMITY (non-serious), outcome "unknown", described as "leg pain"; PAIN (non-serious), outcome "unknown", described as "feeling really achy"; MALAISE (non-serious), outcome "unknown", described as "not feeling well"; HEADACHE (non-serious), outcome "unknown", described as "Headaches".  Additional information: Patient reported that she felt the pharmacist squeeze her arm before giving the vaccine. They're actually supposed to flatten the area to better reach the muscle.  Afterward she was wiping it like crazy, it bled a couple drops, then developed a bruise the size of a dime to a nickel of light discoloration. She received Covid 19 vaccine booster dose adult formulation two weeks ago and it was administered two fingers below the axilla, so about 2 fingers lower than her other two previous injections.  It was in the medial back part of the arm right at the tshirt line where the other two were above the tshirt line.  Its at least 6-8 fingers dodwn from the chromial process of her shoulder although she had small fingers. It was either in the lower part of the deltoid, or not on the deltoid or may be in the tricep. Between her shoulder and elbow its more than half way down. After she got the shot, in her arm, stung and is sore and she had felt, day after the vaccine, back pain, leg pain hurting all over, then  felt a few days of feeling really achy and not feeling well last couple times I've gotten the injection. Headaches. Realized after it is supposed to be given two fingers below acromion process so it's in the middle of the deltoid. Caller was administered her booster dose in her triceps, a good couple inches below the axilla. States her vaccine was given maybe 6 fingers from the acromion process and two fingers below the axilla. Her dose was given near the base or below the deltoid. States she is overweight and can't exactly figure out where the insertion site is. Since hers was given two weeks ago, she guesses she's ok.  She couldn't find anything whether it's effective if given in the wrong place or given a couple inches too low. One website, a doctor said it might not be effective and suggested to check antibodies. She called a couple pharmacies who suggested calling Pfizer. She is nervous because she went through a lot to get the vaccine.   No follow-up attempts are possible; information about lot/batch number cannot be obtained. No further information is expected.