Hi I Am Having Problems With Arm It Started A

Hi I am having problems with arm it started a couple of months with pain in inside of right arm then has now progressed to be swollen hand an arm it's quite painful but very weak. I can now feel my left arm in the inside muscle commencing same way as right what could be the cause of this. Have saw go an he did loads of blood tests an all clear the pain is keeping me awake at night an swelling an weakness don't seem to be shifting