I have pain doing sex. on my left and right side. what could it be?

Pelvic issues?: Pain during intercourse (internal pain, not external or vaginal) is called dyspareunia; often seen with pelvic problems. Could be due to ovarian cysts, infection, tubal problems, including tubal pregnancy, uterine problems bowel abnormalities including crohn's disease, ulcerative colitis, other. See your doc, get examined, maybe sono or other tests.