Can you tell, when it started? Do you have older saves? If you are level 25 now, how was it at level 10? Because maybe some 'game stat' hangs on your character, maybe it did not register you leaving a radiated zone and continued with the effect? You say 'anytime I am leaving my armor' - does this mean, that power armor protects you, if you wear it?
It would be best to find out, when this happened. I do not think this was so at the start? Because you would not have survived this...
Also - did you try to disable all your mods, if you have any? Because a mod could be responsible.
If you wrote to support - did you send them a save? If not, do this, because they can load your save and if this is a bug, they will see it and probably be quick to find the bug.