Hi, I Am A 46 Yr Old Man Who Is

Hi, I am a 46 yr old man who is about 30lbs overweight... A couple weeks ago I woke up around 2am and my heart was pounding and it was a little tough to breathe and my right arm and leg were throbbing with pressure. I walked around for awhile and all went back to normal.. 1 week later the same thing happened again and this time it took hours to get back to normal. I went to the doctor the next day and my BP was 168/108 ( never had a BP issue before). The doctor put me on 10milligrams of lisinopril and it kept me at average for a week but then started to make me have low BP 92/62. So I started to half the pill but the low BP remained. I stopped the BP meds and my BP has stayed around 117/78 with no swings. My EKG was normal as well as my blood tests but they were concerned about my cholesterol. I am worried that I may have a heart issue that caused the temporary spike in my BP and I want to know what kind of tests I can have done to find out.. One more thing, I sometimes have a odd shuddering/fluttering in my diaphragm area
Thanks
Mike