as a 50 year sufferer, this is what helped me be completely symptom free. Pearls High Potency Probiotics and Activia yogurt. I take both every single day and have been pain free for 2 years, after 50 years of pain and suffering. Stick with it, it takes between 2 to 4 months for this to start helping, I started to notice major relief in the 2nd month and complete relief by the 4th month. I still take them both every day. give it a try. If this brands aren't available where you live, google their ingredients, the type of probiotics they contain, and try another product in your country that has similar types of probiotics.
I have tried all diets and prescriptions recommended by the doctors and nothing helped but this. I hope it can help you too.