What Causes Strange, Pulsing Sensation On The Middle Of Back?

Hi
I am getting a strange pulsing sensation on the middle left hand side of my back. It's not painful but just a strange pulsing sensation it pulses really fast then stops it's as if it's coming from my kidney.

I am also getting a strange shooting pain in the inside of my left arm. Only on the inside of the arm and no where else around the arm.

These two sensations are not connected and there is no pattern to them it is random. The arm pain is very uncomfortable and it comes and goes but is can be just uncomfortable or pretty sore.

Any advice would be appreciated.