Hi
Welcome to the MedHelp forum!
If the chest pain is still persisting it can be due to pericarditis of autoimmune origin like in SLE, rheumatoid arthritis etc. It can also be pinched spinal nerve at thoracic spine level. Chest pain aggravated by laughing yawning and deep breathing goes more in favor of costochondritis, which causes pain and tenderness at points where your ribs attach to your breastbone. The inflammation around the joint area gives sharp pain on taking a breath. This can also cause tenderness on pressing the area which pains. Please co-relate this information with the tests done. You will need to consult a doctor to eliminate the causes. Hope this helps. Do let me know if there is any thing else and keep me posted. Take care!
What tests were performed in the hospital?