History: I am a 70 year old African-American woman, 5ft/9in who weights 155 lbs. I have high blood pressure. For this, I take one diovan HCT 320-12.5 tablet and one Crestor 5mg tablet daily for cholestral. (I was first diagnosed with high blood pressure in my mid forties.) It runs in my family. I also take two over the counter Calcium 600 +D usp tablet daily. I am not a diabetic and have not been treated for any heart problems. I have had to take a tablet every day when my potassium was low but I do not remember the name of the drug. But my potassium may be low again because sometimes at night I get terrible pain in one of my legs. I am not a diabetic and do not have heart problems. You should know that I started back walking in the early morning 5 miles daily three weeks ago. I have been doing this off and on since 2005. My question: I have been experiencing pain in my chest area just above my right breast for two days. It started yesterday about 30 minutes after I completed my 5 mile walk. The pain is not constant and feels more like stings when it occurs. When I touch or rub the area, it stops for a while but still comes back. It may stop for even an hour or two before returning. On each return, I repeat the touching and rubbing. It is not the first time I have experienced this. It happened some months ago but I do not remember the exact time before iit finally stopped. What could this be? Thank you very much.