What Causes Sudden Terrible Pain In The Left Arm?

I am a 40 year old female and overall I live a healthy lifestyle besides the occassional stress of my job. I am 5'8 and weigh about 160 lbs., I do not smoke and might have 2 alcoholic drinks a year. I was walking in the mall the other day and started having terrible aching pains in my left arm. It was such a deep ache and it continued for more than 12 hours. I also experienced some cool sensations in my arm, it was very strange. The only other symptoms that I have noticed is that in the last week or so I have been feeling some heart fluttering. Almost like some anxiety feelings, just very strange. I have been checking my blood pressure and its been great and remaining around 125 over 70 and my heart rate is around 73. Should I be concerned and should I go to the doctor?