I constantly get severe heated feeling inside as though i'm going to combust. then i get sweats badly and chills. been going on for years. worse w/act?

Many things: can cause you to have these vague feelings. It may be a simple as you being out of shape or secondary to a health condition. The best place to start is to see a doc for an exam. Alternatively, we can talk at https://www.healthtap.com/experts/12663165-dr-patrick-kohlitz

Further testing: Although at your age these could be menopausal symptoms, they can be related to multiple medical problems. I suggest a full medical and GYN evalaution with hormonal testing and metabolic evaluation.