Legs Cramps / his leg was going to tear; Shingles after he had a Covid 19 Booster Dose by Moderna; This spontaneous case was reported by a patient and describes the occurrence of HERPES ZOSTER (Shingles after he had a Covid 19 Booster Dose by Moderna) and MUSCLE SPASMS (Legs Cramps / his leg was going to tear) in a 50-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 032H21A) for COVID-19 prophylaxis.     The patient's past medical history included COVID-19 in November 2020, Heart rate low from 02-Apr-2021 to 06-Apr-2021, Shingles (had shingles one other time since then too. diagnosed on 12-APR-2021 but the Shingles started the previous week.) from 06-Apr-2021 to 30-Apr-2021, Leg cramps from April 2021 to June 2021, Shingles from February 2022 to March 2022 and Biopsy (7 biopsies for the rash). Previously administered products included for Product used for unknown indication: Pfizer / BioNTech (within a 10 day period after the first vaccine the skin rash started. Time: 10:30, Route of Administration: Standard Dose Injection into Arm, Batch/Lot number: EN6201) on 11-Feb-2021, Pfizer / BioNTech (heart problems and had to be in the hospital because patient would had a low heart rate and then go to tachycardia.) on 11-Feb-2021, Pfizer / BioNTech (shingles started in APR-2021, Expiration: 30-JUN-2021 Time: 10:30 , Route of Administration: Standard Dose Injection into Arm  and Batch/Lot number: EN6199) on 04-Mar-2021. Past adverse reactions to the above products included Shingles with Pfizer / BioNTech; Skin rash with Pfizer / BioNTech; and Tachycardia with Pfizer / BioNTech. Concurrent medical conditions included Skin rash since 21-Feb-2021. Concomitant products included METOPROLOL for Heart rate abnormal, PREDNISONE for Skin rash, ZOLPIDEM TARTRATE (AMBIEN) and CANNABIDIOL for Sleep disorder.    On 24-Mar-2022, the patient received dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) .25 milliliter. In 2022, the patient experienced HERPES ZOSTER (Shingles after he had a Covid 19 Booster Dose by Moderna). On an unknown date, the patient experienced MUSCLE SPASMS (Legs Cramps / his leg was going to tear). In 2022, HERPES ZOSTER (Shingles after he had a Covid 19 Booster Dose by Moderna) had resolved. At the time of the report, MUSCLE SPASMS (Legs Cramps / his leg was going to tear) outcome was unknown.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   The Ethnicity was reported. The Age of the patient was reported as 50. The concomitant medcation was reported as THC for sleep. It was reported that patient took Prednisone and that was the only thing that would clear the rash and was on it for a year.  It was reported that patient can't stand being on Prednisone all the time, so just gets a Prednisone Injection if skin flares up. Patient states currently it is improved, but it ebbs and flows, meaning it can flare up. He states it can be a little spot or had flare ups where whole back becomes a big strawberry. Patient stated the rash is on back and the back of legs. It started at pants line above buttock and then it spread to upper back and then to the back of legs. Patient had 7 biopsies for the rash and had all come back inconclusive and did 3 of the biopsies.  It was reported that patient heart rate would drop to the 30s and then spike up to 130s. Patient reported were able to get it under control with Metoprolol.   It was reported that crams would never stop for 15-20 minutes, and patient never had an experience like that before. Patient stated thought leg was going to tear. They lasted several months, and they would come and go.   No treatment medications were reported.