Hi. It sure sounds uncomfortable.....I think you are on the right track investigating heart disease... It used to be a male dominated disease but now it seems to be affecting more women and people as a whole at younger ages. While I am unclear of your gender, I am not altogether sure it matters anymore.
I wonder, do you have any other symptoms? Taking any medications?
Any back injuries, or Shoulder/ elbow injuries?
There are many things that can cause numbness in various parts of the body.... please do not panick, as,
it may not be serious.