I have a sharp pain in my chest when i cough or sneeze. what causes this?

Fold in the pleura: This is usually caused by a transient fold in the pleura, the lining of the inside of the chest wall. It is a non-problem. If it becomes much worse or is persistent, an office visit is appropriate to rule out spontaneous pneumothorax.

Possibilities...: This pain is likely musculoskeletal if it is not present all the time. Possible causes include strained muscle, cartilage inflammation or a fractured rib, especially if you have been coughing for a while. Once the cough resolves, this pain will improve over time. If not, see your doctor.