Genetics. I have the same very low readings I did at 39. ( almost 63) I still exercise regularly and eat pretty healthily. My mom had sky high readings all her life and died of a stroke, and her dad of a heart attack in his fifties. She also exercised and ate well.
I also had a strange test a couple years ago where my readings were high, but not since.
As far as pain: When I was in the middle of a very stressful business ownership, I had chest and left arm pains on a daily basis. And high blood pressure. When I moved to a less stressful environment the blood pressure dropped, and when I stopped taking high stress projects my chest pains went away. It's been fifteen years since I had them.
I recently ran the treadmill test until the Doc laughed and said he wished he could do that well. But genetics play a huge part.
O, and READ THE LABELS on the statins and think twice about taking them. Ditto all drugs. They ain't kidding when they print the side effects. I had a negative reaction to Cipro ( antibiotic) last time I took it ( tendon pains and knots) and some people have horrible reactions. I met a guy who was disabled from taking Cipro. Statins like Mevacor also have side effects:
Abdominal pain/cramps, altered sense of taste, blurred vision, constipation, diarrhea, dizziness, gas, headache, heartburn, indigestion, itching, muscle cramps, muscle pain, muscle weakness with rash, nausea, rash, weakness.
And it is only supposed to be prescribed if diet, exercise and weight loss fail to work, but so MANY Doctors prescribe that shit like it was a MIRACLE DRUG WITH NO SIDE EFFECTS.
Stay away from prescription drugs if you possibly can. They don't prescribe them because they are good for you, they are out there because the Big Pharma makes Big Money from them. Period.