Shoulder pain and arm spasms

So my husband woke up with his neck hurting. It went away, so he went to the gym. Did his normal lifts.. now he's having strong pain in his left shoulder. Said it feels like millions of needles going into him. It radiates kinda to his left arm. His arm isn't in pain. It's just weak and spasming. I can see it visably twitching. . Any ideas? We're alternating heat/ice, and he took ibuprofen.