What Causes Pain And Tiredness In Arm During Mornings?

I am fitness trainer by profession... early mrngs I feel too much stress on my right arm... weird tiredness through out the arm, especially aftr wight training... pain starts wit shoulder (anterior delt) shift to elbow... even aftr enough rest I feel weakness till small finger... it developed in year.. hv consulted nerologist abt ths prob.. he tld me to hv nervigen 20 (daily 1 in the mrng) bt I wnt a second opinion.. pls help