What Causes Severe Pain In Shoulders And Triceps Along With Stiffness In Neck?

I lift weights every other day. At night following a lifting day I have severe pain in my shoulders and tricep area, both sides. Throbbing nerve pain. My neck sometimes is stiff but no pain in neck. I have little or no pain when I perform exercise. Why does this happen most every night? When I awake and get blood flowing it always goes away. Thank you for your time