Sharp pain on middle of my chest.

Many reasons: Reason can be ardiac, gastrointestinal, or musculoskeletal. If with your chest pain, you have shortness of breat, nausea, vomiting, sweating, or the chest pain goes down your left arm, this maybe a sign of a heart condition. You should call 911 or seek medical attention immediately. If you do not have the above symptoms, i would seek the advice of a primary care doctor.