Are my rats irratated?

i sometimes bathe them when i clean theyre cage and i use a homemade soap recipe i found online they seem to be in pain when i put it on but theres no injuries on them and for a few weeks they get hurt by simple things including when they groom each other and then figt non stop i need help the recipe is take a half of a teaspoon of any shampoo and distill it in a bottle of water for 2 hours and mix well i want to know if this is the problem they als seem itchy and afraid of people