What Causes Occasional Painful Jolt Midway Between Left Elbow And Wrist?

I'll gamble fearing redundance. Midway between left elbow and wrist I occasionally get a good jolt. Heart is fine. Left hand often goes numb right to the extremities and at times can be quite soar. Seems that laying on that side might be the culprit. Just below the elbow occurs any time of day but not very frequently.