Hi @fayda. I hope you find the helpful answers here as so many of us have. So many types of stomach and back pain in usual situations then add the post covid unusual new types of pain🙃 If I may suggest looking into food reactions/histamine intolerance…. I use to eat anything before long haul covid and now I experience many different types of reactions/pain to many foods, spices, drinks…and some here have commented even react to different types of water ie tap vs bottled etc🙃 Keeping a food/reaction diary I found well worth it to verify my issue histamine related. Now I at least have a chance of knowing if it contains for instance cinnamon or spinach I will pay the price in ways I choose to avoid it! Health systems are becoming more aware of this and providing specialized nutritionist thru post covid clinics. Wishing you quickest recovery🌈