Heaviness in Breathing/breathing problems; felt different; not feeling good; Aggravated Asthma; horrible acid reflux/ Aggravated Acid reflux; was in pain last night/she was really hurting; blood pressure was sort of up to like 185 over 186; Chest pain; back for stabbing pain; Pressure chest; Wheezy; This is a spontaneous report received a contactable consumer (the patient). A 66-year-old female patient received the first dose of BNT162B2 (PFIZER-BIONTECH COVID-19 MRNA VACCINE, lot number not reported), via unspecified route of administration in the left arm on 01May2021 (at the age of 66 years-old) as a single dose for COVID-19 immunization. The patient's medical history included a "heart condition", asthma, acid reflux, hiatal hernia, and being "allergic to a lot of medications", reporting that she previously had to carry an epinephrine (EPIPEN). The patient had unspecified concomitant medications. The patient stated that immediately after the first dose, she started not feeling good (01May2021), and by the time she got home, she was really having some breathing problems (01May2021).  She was monitored at the vaccination site for 30 minutes after administration, but did not report to them, because she did not know what to tell them. She a history of asthma, so she treated with her inhalers, and "it eased off a little bit".  She reported she was really hurting, so she took a 5 mg dose of prednisone tablet. She also reported horrible acid reflux later that night (01May2021), which can trigger her asthma, she took some aluminum hydroxide/ magnesium hydroxide/ simethicone MYLANTA and felt much better.  She slept propped up, took another dose of MYLANTA this morning, and was feeling better today, but not 100%. She wanted to know if the vaccine can cause acid reflux or asthma exacerbations? And if she should expect the same, but more severe reactions after the second dose?  It was also reported, that after the vaccine, the patient stated for fifty minutes maybe she had what was like pressure in her chest (unspecified date May2021). She did not know what she was feeling, so she did not say anything. So she came home, and just as the day got work more the pressure, she had asthma and saw what was happening was an asthma attack, which started hurting really bad like an asthma attack, so she took her inhalers, and it eased it off a little bit. Then it just kept worsening. She was also a heart patient, so when she had asthma, some times it mimicked a chest pain. She was thinking if it was affecting chest pain or was it asthma, so had some prednisone, 5mg of prednisone (treatment) that she had to take for her asthma. It did not help last night (further clarification unknown). She was trying to get to the hospital. She was wondering if this shot had aggravated her acid reflux and aggravated her asthma (both 01May2021). When the patient went to bed, she got some aluminum oxide/ magnesium hydroxide (MAALOX), big dose of MYLANTA, and that eased it off. Before she got the shot, she felt fine; she would have no symptoms, and then when she got the shot  "mean it went 30 minutes later and I just felt this and I still did not know what it was". Her husband told her to sit down. She did not know what was wrong, she just felt different. She thought it caused her asthma to act up. The patient stated that last night (01May2021), her blood pressure was sort of up to like 185 over 186, "but I think it was because I am extreme so bad by then I am and my chest in my chest and then I finally said okay let me take so (incomplete sentence) my acid reflux so let me take some MYLANTA so I take calcium carbonate/ magnesium hydroxide (ROLAIDS) and I immediately stop that pain that must be my acid reflux making triggering my asthma it is, I was like, I was in pain last night (01May2021), just administered for my asthma between my chest and my back for stabbing pain (01May2021) and that caused sometimes when I have heart condition, I always like it is my heart or it is my asthma what is it? and I got this one okay I will take a dose of MYLANTA just to make sure see that will help come down". The patient felt a lot better today, but still felt sort of wheezy (May2021) "like you know when you have asthma". Her bad asthma she would just get a wheezy sort of just heaviness in breathing. The patient was due to get the second shot on 22May2021. On an unspecified date, the patient had: a lab test "but have results before I had the following to chest by giving lastly", and routine blood work-cholesterol and all. The outcome of the events wheezy, heaviness in breathing/ breathing problems, horrible acid reflux/ aggravated acid reflux was recovering. The outcome of other events was unknown.  Information about lot number has been requested.