What could it be that is putting him into this much pains, doctors cant find anything yet.?

Hi my other half is in alot of pain and the doctor's aint really sure what it is and in the blood test it all came out clear... our problem is he has had the problem over 4 months now. he keeps having headaches and feeling like he's going to p out, he's always nevours that he's going to die.. he's vains in he's hand are all swallen and in pain plur it goes nump whilst they are swallen, he's foot hurts cause of all the pain he's having and he sas it seems like he's got an empty mind and doesnt want to think of anything because he's in too much pain. i dont know if anyone could give us an idea what it could be..