Why does my lower back hurt when im on my period ?

Varies: Women may experience different symptoms during menses. it varies and may include bloating, breast tenderness, headache, nausea, vomiting, abdominal pain, back pain, etc. Some women may experience almost no symptoms while others literally cannot function. See your doctor if common over the counter medication such as ibuprofen , acetaminophen; and warm pads to your back doesn't help.