Shortness of breath with sharp pain in chest and right arm can be caused by heart disease, such as acute pericarditis, myocardial ischemia. You should take ECG, UCG, myocardial enzymes to assess the situation. Your symptoms also may be caused by pneumothorax or pulmonary embolism. Next time you have an acute attack of chest pain, you should get a chest CT scan.
For taking Benadryl for the anxiety , you should check with your psychologist whether you need to take it for a long time.