On my left hand, there is a stabbing pain between my index finger and thumb whenever i move them, what's wrong with me?

Hand pain: Stabbing pain is most of the time muscular in nature. However, tingling and numbness/weakness would be a sign of nerve entrapment (carpal tunnel syndrome). Stop texting for a while and it should get better. Texting can also lead to cervical spine strain and disc damage+nerve entrapments. Use heat twice a day for at least a week. Immerse your hand in warm water and exercise by opening and closing.