What Could Be The Reason For Lower Pelvic Pain, Shoulder Pain, Headache, Nausea And Water Retention?

I m a 40 year old woman experiencing lower pelvic pain which moves from one side to the other, I ve had lower back pain as well as shoulder pain, headache, nausea, water retention and a one day light period. Pelvic pain has been constant for 2 weeks What could be the reason?