Well, there are those medications on TV on ads, where they ALWAYS have these "side-effects", and the MAJORITY of them include heart-pain.
I hope I helped! :-)
Firstly, I should place the patient in the recovery position. After that, I should activate the EMS, which may include giving him CPR. I should tilt their head and list their chin up, in order to open their airway. If they are still not breathing, I should call the ambulance.