My wife feels really hot especially in the upper body. sometimes i can feel this heat and sonetimes not. she has no signs of fever. it's been 3 weeks.

Could be many things: She needs to get checked out. Touch is not a very good test of temperature since it is dependent on feeling the difference between tow objects. A more objective test might be required. Also, a simple body temperature reading like temporal or oral temperature would be more objective. A complete exam with possibly some lab tests like a blood count and cmp may also help sort out what is going on.