My hair roots and scalp hurts for some reason. I am not sure why, I don't really use any products.

Is there any advice? I also never really get much stress and I have a pretty good diet. Maybe I don't drink enough water? Anyways thanks, and I look forward to your reply. except for shampoo. I don't use anything else. I never tie my hair up or do anything. I comb it once a day but that is very painful, if the wind blows on it, it is also very painful. I am not sure what the cause is. Some days it is here, and some days it isn't. I have noticed that I am shedding hairs quiet frequently