What Causes Total Body Pain?

My husband is 50 years old and is suffering body pain in his shoulder, arms,elbows,hipe,legs, knees down to his feet, it's getting progresivley worse and he is getting depressed. he has had endoscopy and colonoscopy, all clear, he has had ct scan on abdomin and chest, all clear, all blood test ranginf from cancer to viral disease are also all clear, he does have an inflamed bursa in his left shoulder found in an xray, the doctor has been very thourough, but doesn't have any answers and doesn't no where to go from here.