Painful itching on entire body, upper body precisely ?

This problem arises when heat pores of your body gets blocked . Heat pores of body are responsible for emitting out excess heat trapped in the body. To get rid of this you've to open your skin pores as soon as you possibly can. 

How to open skin pores ?

Steam bath is best possible solution known to open skin pores as it clears any dirt trapped inside the pores and open them. You can also consult your doctor to prescribe you some ointment or creams which will open skin pores.