Can someone diagnose my symptoms PLEASE!?

Today is May 13th 2011 and I have had a persistent cough since December 15th 2010. In the begining it was dry but has become more and more phlem productive over time. My doctor has drawn blood and it showed nothing unusual. I developed the wierdest symptom around February. I have extreme pain in my left hand that is relative to temperature. The colder it is the more my hand hurts. I would describe the pain as exactly the same as a cavity in a tooth type of pain if you can try to imagine that in your hand. The joints are also stiff and sensitive as iff I have jammed all of my fingers. When it hurts badly, the pain seems to spread in a contagious manner which I have come to refer to as a "flare up". During a flare up the pain will spread into my left elbow. Then my left foot will start to throb and have the same pain, followed by my right hand then right foot and always in the same order. If I take a hot bath or shower I recieve relief within 5 to 10 minuits of getting warmed up, but the pain will return upon cooling down. Unfortunatley "cool" would be anything under 90 degrees F and I simply can't stay in an enviroment warm enough to prevent pain without sweating like a pig. I am stuck between the rock and hardplace of either being in pain or being uncomfortably hot, plus I have a cough that will not go away. My doctor is bewildered as am I. Please help. I live in Phoenix Arizona, I work in construction, I am 33 and a Hispanic male in good physical shape other than the symptoms with no family history of disease other that an aunt with breast cancer and an uncle with diabetes. Fataher and grandma had heart attacks in thier 70s. Mother had a thyroid thing. Thats about all thats ever been wrong with anyone in my family. I used to wrestle and my doctor suggested a pinched nerve in my neck, but x rays looked good, and there was no injury recently, although years ago there have been injuries and those injuries did cause tingling in my extremeties and cold sensitivity. However, why the cough then? Thanks again.