Feeling uterine pain during menstruation may be dysmenorrhea, and non-menstrual period may be related to pelvic inflammatory disease, adenomyosis and other diseases. 1. Menstruation: During a woman’s menstruation, the endometrium secretes prostaglandins. If too much prostaglandin is secreted, it will lead to uterine ischemia and hypoxia, and then dysmenorrhea. 2. Non-menstrual period: (1) Pelvic inflammatory disease: Pelvic inflammatory disease may have different clinical manifestations depending on the severity and extent of inflammation, and the mild cases are asymptomatic or have mild symptoms. Common symptoms are lower abdominal pain and increased vaginal discharge. Abdominal pain is persistent and worsens after activity or intercourse. If the condition is serious, fever or even high fever, chills, headache and lack of appetite may occur. (2) Adenomyosis: Patients with adenomyosis can suffer from dysmenorrhea due to the invasion of the endometrium into the muscular tissues of the uterine wall, which can be congested, swollen as well as bleeding under the influence of ovarian hormones. There are many reasons for feeling a little pain inside the uterus, and it is recommended that patients seek medical attention in time, under the guidance of the doctor for relevant examinations, clear diagnosis and timely treatment.