I'm 20 years old and have been having random sessions of sharp chest pain, mostly during inhalation. What could be the the possible cause?

See the doctor. In a young person, cardiac disease is uncommon, but it can happen and pain with inspriation can be a sign of lung disease, pleursey or a fractured rib. I would see my physician as soon as possible.
It could be. There are several causes for chest pain. Only when you go to your doctor and get checked you will know the answer.