[Ambedo.]

I've never taken Metformin, but I did do a quick Google search and, according to the National Library of Medicine, gastrointestinal side effects occur in roughly 75% of patients who take it. If you're interested in reading more, you can do so here.

If it's something you're concerned about or that is causing a lot of problems in your daily life, I would definitely recommend speaking to your doctor about it! They may be able to prescribe an anti-diarrheal or recommend changes you can make in your daily life to help minimize the side effects. Additionally, making them aware of the side effects you're experiencing will allow them to log it and track whether or not they decrease, increase, or remain the same during follow-up visits, which gives your doctor the opportunity to adjust your treatment/dosage/medication accordingly.