If you had a build up of radiation this would be quite dangerous so would act as a force field as nobody would want to come near you! The radiation could be heat and so you wouldn’t be so happy in the middle of it, or gamma radiation and then you would be radioactive so get sick.
Radiation is more physics based than my knowledge goes, but we do deal with radiation in the lab so I know a bit about it. You definitely wouldn’t want to be surrounded by radiation at all- and it wouldn’t be very good for you, depending on the type of radiation it is. As Jo said, it could also be very warm!
Most radiation is pretty damaging to people, so you could get sick very quickly. Some of them could also lead to death in a short time if there was enough of it.
You could build a ‘force field’ of sorts to keep it out. For example, certain types of radiation can be shielded by different things. Low-energy radiation is simply stopped by air- if you’re far enough away, it’s not a problem. For higher energy you might need thick plastic/glass or even thick lead to stop it!
I don’t know about the human body, but the closest thing I could find to the ‘force fields’ that appear in science fiction is a suggested idea for protecting space craft from harmful radiation in space.
Space is full of ‘cosmic rays’ from various sources, and this would be a problem for space travel because astronauts would be at risk from cancer if they travel too far away from the Earth.
A suggested solution for this is to use a ‘plasma’ – which is like a very hot gas where the atoms have been ripped apart – enclosed in a metal mesh around the spacecraft. Apparently this would be equivalent to a shield made of aluminium several inches thick.
I wouldn’t like to wear a suit made of this, but it will be quite cool if we protect spacecraft with force fields like this in future!