What Causes Throbbing In Biceps And Twitching In Legs?

I'm 5'1 210# 39 y/o white female, hx of high bp and choles. family hx of hypertrophic cardiomyopathy (my brother). But it has been ruled out for me.I'm having throbbing sensations in my left arm and dizziness on and off. Was out walking and everytime I allowed my left arm to hang it throbbed in the bicep. No pain and I haven't done any weight lifting. Just started a walking regimen yesterday after a 6 month break. I did show signs of damage on the echo... I have twitching in my left leg now that I've sat down, likely related to the walking though. any thoughts?