My Husband Is Having Sever Pain In His Right Shoulder

My husband is having sever pain in his right shoulder pain. It started in his upper right arm 4 days ago and migrated to his upper right shoulder area. Went to the ER at 5 AM where he was told it was a pinched nerve and was given a long and short anesthesia with a steroid (kenalog) shot in that specific area. Seemed to knock the pain down a bit, but here 5 hours later, he says it is back at an 8 out of 10 scale of pain. Blood pressure good (124/84), no nausea, doesn't hurt to breath. Didn't do anything physical to strain it. Been working at a computer. How long does it take this kenalog to kick in?