A 72-year-old patient complains of a rash, intense pain in her right subscapular region, general weakness, and fever of 37.7°C. According to the patient's medical history, the disease onset was three days ago. Objectively, grouped vesicles with transparent contents, arranged in a line, can be detected in the right subscapular region on hyperemic, slightly infiltrated skin. What is the most likely diagnosis in this case?