I'm hurting under my left shoulder blade when i cough, sneeze, yawn , take a deep breath, or laugh sitting up or leaning forward does help?

Pleuritis: Unless you have a rare deformity of the underside of the scapula, the best bet is pleurisy. The lining of the lung is separated from the moving tissue by a fluid that occasionally is lacking in one spot and gets stuck. The irritation can persist and rarely requires medical help. Almost always you can wait and see if it is a transient and intermittant irritation.