I'm 22 years old and I have sharp lower left abdomen pain that shoots down my left leg. What could be the reason for this.

Go to see doctors... Collect and record the feature and degree of your symptoms with their detailed sequence of events, with attention to if physically related or not, and bring those to see doctor who will usually be able to sort out what is going on in you and advise you what to do after reviewing what you bring, history, physicals, ... But, reasonable to think of pinching nerve? Intra-pelvic adhesion? Or ... Best.