made pain worse; Sleeping is painful; Walking is painful; I felt a slight sort of twinge/fluttering from the shot location across my back/ neck but it didn't hurt at the time; Stiff neck on opposite side from injected arm/Pers. neck pain opp side; This spontaneous case was reported by a consumer and describes the occurrence of MUSCULOSKELETAL STIFFNESS (Stiff neck on opposite side from injected arm/Pers. neck pain opp side), PAIN (made pain worse), INSOMNIA (Sleeping is painful), GAIT DISTURBANCE (Walking is painful) and VACCINATION SITE PAIN (I felt a slight sort of twinge/fluttering from the shot location across my back/ neck but it didn't hurt at the time) in a 51-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 034C21A and D26B21A) for COVID-19 vaccination.     The patient's past medical history included Accident automobile (Over 30 years ago) and Trauma. Concurrent medical conditions included Drug allergy, Allergy to antibiotic, Allergy to antibiotic, Asthma, Depression and Anxiety. Concomitant products included LORATADINE, PSEUDOEPHEDRINE SULFATE (CLARITIN D 12 HOUR) for Allergy, ALBUTEROL SULFATE for Asthma, VORTIOXETINE HYDROBROMIDE (TRINTELLIX) for Depression and Anxiety.   On 05-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 23-May-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 23-May-2021, the patient experienced MUSCULOSKELETAL STIFFNESS (Stiff neck on opposite side from injected arm/Pers. neck pain opp side). On an unknown date, the patient experienced PAIN (made pain worse), INSOMNIA (Sleeping is painful), GAIT DISTURBANCE (Walking is painful) and VACCINATION SITE PAIN (I felt a slight sort of twinge/fluttering from the shot location across my back/ neck but it didn't hurt at the time). The patient was treated with IBUPROFEN ongoing since an unknown date for Adverse event, at a dose of 1 dosage form and MENTHOL (BIOFREEZE PAIN RELIEVING) ongoing since an unknown date for Adverse event, at a dose of 1 dosage form. On 17-Jun-2021, MUSCULOSKELETAL STIFFNESS (Stiff neck on opposite side from injected arm/Pers. neck pain opp side) had not resolved. At the time of the report, PAIN (made pain worse), INSOMNIA (Sleeping is painful), GAIT DISTURBANCE (Walking is painful) and VACCINATION SITE PAIN (I felt a slight sort of twinge/fluttering from the shot location across my back/ neck but it didn't hurt at the time) outcome was unknown.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered MUSCULOSKELETAL STIFFNESS (Stiff neck on opposite side from injected arm/Pers. neck pain opp side) to be possibly related. No further causality assessments were provided for PAIN (made pain worse), INSOMNIA (Sleeping is painful), GAIT DISTURBANCE (Walking is painful) and VACCINATION SITE PAIN (I felt a slight sort of twinge/fluttering from the shot location across my back/ neck but it didn't hurt at the time).    Patient reported pain beginning with second vaccine dose. Pain was not relieved by treatment medications, by icing, or by massaging.   Most recent FOLLOW-UP information incorporated above includes: On 07-Aug-2021: Additional information received included reporter, new events of vaccination site pain, pain, sleep difficult and walking difficulty were added and vaccine details updated.