Lower Left Back Pain Female Pain In Lower Left Of Stomach, What Could It Be? 18 Year Old Female.?

Pain in lower left of stomach, what could it be? 18 year old female.? - lower left back pain female

I am a woman of eighteen years, I recently had severe stabbing pains in the lower abdomen. normally begins either behind the hip or a few inches from my navel on the left. The pain does not last long, but when it starts, is acute pain, and sometimes I'm often holding his stomach and on the floor because of it.
that no matter what I do, the pain occurs at different times.
What is it?