What Ammonium Chloride? And why is is burning my hair when i use a shampoo that has it, as an ingredient?

I have been washing my hair with the same shampoo for the last 20yrs and these last couple of weeks for some reason when i wash my hair is been burning the heck out of my scull. I started reading the ingredients and the only thing that caught my attention was ammonium chloride. Why?What Ammonium Chloride? And why is is burning my hair when i use a shampoo that has it, as an ingredient?
It may have changed the pH of the shampoo and that's what's irritating your skin.What Ammonium Chloride? And why is is burning my hair when i use a shampoo that has it, as an ingredient?
Ammonium Chloride is a mild acid, That is why it might be bothering you. But if you have been using it for 20 yrs I am not sure why it is bothering you now. Have you changed any other types of hair product that might be reacting with it?