Hello, im a 17yr old female and i have really irregular periods that are usually not painful, butt suddenly today my stomach has been in so much pain ?

Painful period: You can take some ibuprofen, Motrin, Advil or Aleve. Usually two or three tabs every 6-8 hours, to help with pain. The cause could be that you have an ovarian cyst, which is common during your period but should not give you that much pain. If the pain does not go away after taking medication, it is important that you go into the office for exam and possible pelvic ultrasound. Feel better!