Theres a really good set of pages on the NHS about IBS. Even includes a dieticians video and an app you can use if you like. The FODMAP diet really has helped me. The initial pain was so severe that I was being sent for scans in case it was appendix or ovaries trying to explode on me again! When the pain gets bad I use Buscopan, which can be available on prescription. When I am taking a break for a holiday etc, and want to relax the diet a little, then I use peppermint oil or tea, or sauerkraut or other probiotics. The probiotics that are best for you, depend on if you have IBS type C, D or A.
https://www.nhs.uk/conditions/irritable-bowel-syndrome-ibs/