Numbness in my heals on my feet, numbness/tingling in my thumbs and electric shock sensation in my arm. What is it?

Without knowing. Details about you as a patient its tough to give a definitive answer. The first thought that comes to my mind is neuropathy. If you have uncontrolled diabetes, then that would be one possible cause. The treatment would be aggresive blood sugar control and use of medications in the class of neurontin (gabapentin). Nerve compression causing these type of symptoms are a possibility though not as likely....
Electric shock bad. You could have symptoms of neuropathy but the electrical shock sensations are disturbing until you are seen by your family dr. And possibly an MRI of your cervical spine is done to make sure there's not compression of the spinal cord. Electrical shocks in the arm or body are very bothersome to neurosurgeons until you can prove it's not problematic. Please see your dr. Soon. Good luck.