Hello everyone :) Girls, maybe someone has encountered this: when sitting…

Hello everyone :) Girls, maybe someone has encountered this: when sitting in one position/long time standing on your feet starts to hurt badly in the left lower rib cage. After sleep everything passes, the pain begins in the middle of the day and intensifies in the evening. For a week already. Was for a scheduled checkup, gynecologist prescribed a diet. Says pancreatitis. Doesn't help, and I feel that the pain is not related to food intake at all. 20 weeks pregnant. Suspect it's musculoskeletal. What do you think? Thanks in advance for answers)