Well my toenails are impacted pretty bad and I am having so nail issues. I can very much relate to it hurting to cut or file. I have thick nails on some areas so there are clippers for thicker nails. Mine are still very hard though to do.When I try to file I do it for a very short time. I hold my toe as light as possible but so that the actual toe can't move. If it moves the pain goes up too much and sends a flare.
Kathy gave a good idea about the warm water. I have been soaking my feet because I am having some sores and toenail issues. Not sure if it is helping.
I hope you can find what works for you.