Was late a week & 1/2 last month & again I am 3 days late this month with horrible right side pelvic pains but neg test... What could it be?

Need evaluation. by an experienced healthcare provider. The horrible right sided pelvic pains could be due to an ovarian cyst and/or pelvic inflammatory disease (PID). PID can be very dangerous and lead to scarring of the tube and problems with fertility. PID is most commonly caused by a sexually transmitted disease, but can result from other infections that are not sexually transmitted. .