Arm felt like a burning feeling; It was difficult to raise my arm /no improvement in mobility/inability to raise my arm; Deltoid area still hurts/left arm was still pink and sore/arm was still hurting; Skin felt inflamed; Warm on my cheeks, head, neck, torso and arms/additional pink areas of skin on my left arm that were oval shaped, dark pink and warm; Left arm area around the injection site was warm; Left arm area around the injection site was swollen/felt too swollen to lay on that side/upper arm area was raised; Left arm area around the injection site was pink/additional pink areas of skin on my left arm that were oval shaped, dark pink/ left arm was still red; Temperature was 100.0F; Left underarm was swollen, warm and painful; Left arm area around the firm; This spontaneous case was reported by a patient and describes the occurrence of VACCINATION SITE WARMTH (Left arm area around the injection site was warm), INFLAMMATION (Skin felt inflamed), FEELING HOT (Warm on my cheeks, head, neck, torso and arms/additional pink areas of skin on my left arm that were oval shaped, dark pink and warm), MOBILITY DECREASED (It was difficult to raise my arm /no improvement in mobility/inability to raise my arm) and BURNING SENSATION (Arm felt like a burning feeling) in a 37-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 939903 and 041L20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Hypothyroidism. Concomitant products included LEVOTHYROXINE SODIUM (LEVOTHYROXIN) for an unknown indication.   On 17-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 17-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 28-Oct-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 30-Oct-2021, the patient experienced VACCINATION SITE INDURATION (Left arm area around the firm). On 30-Oct-2021 at 2:29 AM, the patient experienced AXILLARY PAIN (Left underarm was swollen, warm and painful). On 30-Oct-2021 at 3:26 PM, the patient experienced PYREXIA (Temperature was 100.0F). On 30-Oct-2021 at 9:33 PM, the patient experienced VACCINATION SITE WARMTH (Left arm area around the injection site was warm), VACCINATION SITE SWELLING (Left arm area around the injection site was swollen/felt too swollen to lay on that side/upper arm area was raised) and VACCINATION SITE ERYTHEMA (Left arm area around the injection site was pink/additional pink areas of skin on my left arm that were oval shaped, dark pink/ left arm was still red). On 30-Oct-2021 at 10:17 PM, the patient experienced INFLAMMATION (Skin felt inflamed) and FEELING HOT (Warm on my cheeks, head, neck, torso and arms/additional pink areas of skin on my left arm that were oval shaped, dark pink and warm). On 31-Oct-2021, the patient experienced PAIN IN EXTREMITY (Deltoid area still hurts/left arm was still pink and sore/arm was still hurting). On 01-Nov-2021, the patient experienced MOBILITY DECREASED (It was difficult to raise my arm /no improvement in mobility/inability to raise my arm). On 30-Nov-2021 at 10:55 AM, the patient experienced BURNING SENSATION (Arm felt like a burning feeling). At the time of the report, VACCINATION SITE WARMTH (Left arm area around the injection site was warm), INFLAMMATION (Skin felt inflamed), FEELING HOT (Warm on my cheeks, head, neck, torso and arms/additional pink areas of skin on my left arm that were oval shaped, dark pink and warm), MOBILITY DECREASED (It was difficult to raise my arm /no improvement in mobility/inability to raise my arm), BURNING SENSATION (Arm felt like a burning feeling), PAIN IN EXTREMITY (Deltoid area still hurts/left arm was still pink and sore/arm was still hurting), VACCINATION SITE INDURATION (Left arm area around the firm), VACCINATION SITE SWELLING (Left arm area around the injection site was swollen/felt too swollen to lay on that side/upper arm area was raised), VACCINATION SITE ERYTHEMA (Left arm area around the injection site was pink/additional pink areas of skin on my left arm that were oval shaped, dark pink/ left arm was still red), AXILLARY PAIN (Left underarm was swollen, warm and painful) and PYREXIA (Temperature was 100.0F) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 30-Oct-2021, Body temperature: 100 (High) at 3.26pm- 100.0 F, at 9.33pm- 99.8 F. On 31-Oct-2021, Body temperature: 98.3 (normal) at 5.54am- 98.3F, at 10.19pm- 97.0 F.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   Patient reported that, on 30-Nov-2021 at 3.26pm her temperature was 100.0F and at 9.3pm her left arm area around the injection site was swollen, warm, firm, and pink, it felt too swollen to lay on that side and temperature was 99.8F. On 30-Oct-2021 at 10.17pm her skin felt inflamed and warm on my cheeks, head, neck, torso and arms and left underarm was swollen, warm and painful.  On 31-Oct-2021 at 2.29am her deltoid area was still hurting and at 5:54am her temperature was 98.3F. On 31-Oct-2021 at 11.25am she had additional pink areas of skin on left arm that were oval shaped, dark pink and warm. On 31-Oct-2021 10.19pm her body temperature was 97.0F. Through the day the left underarm swelling continued. On 01-Nov-2021, at 12.53pm her left arm was still red, warm, swollen, firm and at  2.10pm patient felt difficult to raise her arm, where range of motion had previously been normal. On 02-Nov-2021 at 2.26am, patient could not raise left arm. The upper arm area was raised, dark pink, and swollen and  at 2:45am arm was still warm at the injection site, swollen under the arm, and she could not raise her left arm. On 03-Nov-2021, 1.33pm the upper arm was still pink, swollen and firm. On 03-Nov-2021, 10.53pm left arm was still pink and sore and patient could not raise the arm. On 30-Nov-2021, 10.55am her arm was still hurting and she felt like a burning feeling and still had no improvement in mobility. On 03-Dec2021 at 9.30am, patient visited an orthopedist, PA-C. Patient stated that she wanted to report the adverse, prolonged arm swelling, firmness and inability to raise her arm. Patient had an ample amount of time and rest, but still she cannot raise her arm.  Patient used ice bags and a cool compress.