The aim of this study was to investigate the association between PMS (premenstrual syndrome)-related pain among young women following a particular type of diet during the COVID-19 pandemic. This was compared to the period before the pandemic. Furthermore, we aimed to determine whether the increase in the intensification of pain was correlated to their age, body weight, height and BMI, and whether there are differences in PMS-related pain between women who differ in their diet. A total of 181 young female Caucasian patients who met the criteria for PMS were involved in the study. Patients were divided according to the kind of diet they had followed during the last 12 months before the first medical evaluation. The rise in pain score was evaluated according to the Visual Analog Scale before and during the pandemic. Women following a non-vegetarian (“basic”) diet had a significantly higher body weight in comparison to those on a vegetarian diet. Furthermore, a significant difference was noted between the level of intensification of pain before and during the pandemic in women applying a basic diet, a vegetarian and an elimination diet. Before the pandemic, women from all groups felt weaker pain than during the pandemic. No significant difference in the intensification of pain during the pandemic was shown between women with various diets, nor was there a correlation between intensification of pain and the girl’s age, BMI, their body weight and also height for any of the diets applied.