It will not let any of my chars research.....it says cannot prioritize (research is a long term task)....wtf??
Your should disable all other task's at your main researcher, so only research stay active.
If you got hauling and cleaning enabled, they rarely will go for research. And you notice self, you can't force anyone to do research.
Alternative you can use Fluffy WorkTab mod, and set the prioriety of Research for that pawn higher.
As Canute said you should disable all other tasks since Research is a low priority for some reason.
If you don't use mods or prefer vanilla enable manual priorities and set Research to "1" while the others are 3 or 2.
Also if you were able to prioritize you might end up forgoting the pawn and it will probably end up starving if the mental breaks don't get to the pawn first
I usually leave researchers on priority 2 with research. They still get 1's for things like fighting fires, doctoring (if they're doctors), and flipping switches. Depending on their skills maybe they do something like recruit prisoner --> research (so warden and research both 2, everything other than immediate priority tasks set to 3 or lower so they'll only do them if someone else is using the research bench, in this case typically cleaning or hauling).