I started having stomach pains 4 days after sex and still hurting. I had sex Friday night and didn't start hurting until Tuesday morning when I woke up. I am on birth control and also took the plan b pill. But I weigh around 190, I've read that the pill is less effective in heavier women. It hurts to move or lift heavy things at work. Could it just be a bruised cervix or what? I didn't start feeling the pain until like I said 3 to 4 days after.