Although it is good that your doctors say that you don't have anything serious I would err on the side of caution and ask for a second opinion
from another doctor preferably with expertise in heart complaints. In all likelyhood he will agree with the previous doctor.
The symptoms of numbness
usually have a physical cause. I wonder if you started or stopped or changed the dosage in any medication around the time that you developed the chest pains and numbness in both arms.
Try cutting down or out caffeine and especially aspartame (contained in many diet foods/drinks) and see if after 3 months if you are any better.
I would be cautious of taking xanax
. Xanax is highly addictive and very hard to get off due to withdrawal effects. Also xanax like other sedative type drugs actually can slow down the heart rate
which is not what you want as your heart rate is low.
If you are taking any non-essential medications you could try cutting down the dosage slowly and maybe coming off them completely to see if it is not a toxicity issue from long term usage of a drug. This includes non-essential over the counter drugs.
I hope this helps and I hope your health improves. Hopefully in time this will pass. You could pose the question again, listing all the drugs you took in the 3 months prior to these symptoms and in the weeks and months after symptoms developed etc and diet and life style etc if you have left anything out which was possibly relevant and seeing if anyone can relate etc.