On my rt side behind my breast it hurts,,,, i had a cough about a month and1/2 ago and now when i sneeze, cough or try to clear my throat it hurts ?

Get breast examined: Could be a muscles strain breast area from coughing but given yor age you should perform self Breast exams to check for lumps and get examine by a doctor

Chest pain-cough: You may have developed a lingering infection that caused the cough. You should see your doctor about an examination and a chest x-ray to determine the cause of the chest pain and treat it if necessary.