Plan B and abdominal pain?

I am 18 years old and I have had mild but somewhat consistent lower abdominal pain, Ive gone to the doctor and have had an ultrasound that came out negative for ovarian cysts and whatnot. In february I had to use plan B twice in one month because i started having unprotected sex with my boyfriend. my period was a few days late after the second time i used plan b. I have started using normal birth control since then, but i was wondering if the use of plan b more than once could cause this?
I am also concerned of PID? IBS?