My Husband Is 65, In His Back Especially Just Below

my husband is 65, in his back especially just below his left shoulder blade near his spine he has been getting pain every evening around sunset. He does have a herniated disk in that area. The pain hits and goes from about a 2 to a 10 within about 10 min. He talked to his doctor who prescribed tramadol. This does not seem to help much. He tries hot showers, keeping a warm heated blanket on it. If he takes the blanket off just long enough to go to the bathroom the pain will start. Any ideas. Could he be having a heart attack because his heart does start to race and the left side of his chest starts to hurt. No pain in his arms.