Talk to Internal Medicine on BP, ECG Reports

Few Days Back My Father BP Was High all night and even at morning whenever checked, also had heaviness/pain in left arm and chest. Went to check ECG. It was normal.BP also got normal. At the time of ECG had pain as well but still ECG is fine. He still had been Complaining about heaviness left hand and chest but after few hours he is saying now there is no pain. This has happened second time.My Questions are: Why was the pain ??? Why was BP High even after eating medicines ??? Any suggestions ???