Occasionally, the left side of the abdomen Center always faint pain

I nearly the past two months, the left side of the abdomen Center always occasionally faint pain by hand instead hurt, will be a day when the menstrual period pain, hurt, pain after lying down always feel a sense of falling, and stomach swelling, occasionally feeling inside the bubble flow. whether this is what disease? requested! Thank you!
Hello! If your abdominal pain during menstruation aggravated endometriosis or pelvic inflammatory disease, it is recommended that you go to the hospital gynecological examination confirmed if it is convenient, you can come to the gynecological examination.