Random (repeated) chest pain

5foot 4 inches 46 year old female, 135 lbs. Non smoker, moderate alcool consumtion, no history of heart disease in family ( mother had stroke but heavy smoker, diabetis, drinker, overweight).
This started quite a while ago, had same symptoms before (maybe a year or so ago) but they rarely appear.
I get pain in the middle of my chest, lower rib cage, appx 2 inches above the xyphoid process. Pain in moderate and very localized. It appears for no apparent reason and leave within minutes and may reapear.
No other discomfort, no sweating, no shortness of breath, nothing, never any pain on exertion. I jog and never had problems.
Very random. I exercise imoderate to intense levels, i consider myself an athlete, jog, cycle, weight training, kayak in other words, very active. My diet is good, low fat, high fibre. Had high (very high) cholesterol levels 3 years ago but brought them down with weight loss and diet.