I am originally from Nepal but from past 22 months I am working in Qatar. These days my hair is falling continuously . I am 25 and my hair started turning white on back of my head. And there is pimple or worn like I fell in head and also a root of hair makes a pain lot

You need to see a doctor right away. You could have a parasite. Also your nutritional state could be off adding to the cause of your problems.

One of the best methods to hair growth is applying natural oils. There are various oil available on market for the hair growth. Olive oil is the one of the best natural oil available for the hair growth. Mix olive oil with coconut oil. Then heat the mixture up to warm. Then directly apply the mixture on hair. After 25 minute wash the hair normally.
Almond oil is the one of the best oil for skin and hair. It contain rich of vitamin A ,B ,E. which eliminate the dead cells from skin. Almond oil contain magnesium ,magnesium deficiency will lead to heavy hair fall. Using almond oil will stop the hair fall very well. Caster oil also good for the hair growth. I t is best for hair re growth.
More than this natural hair treatment proper exercise also reduce the hair fall very well. It improves the blood circulation for hair and skin. Avoid expose of hair to excess heat. Don’t wash your hair daily with anti dandruff shampoo ,use it for twice in a week. Always use a mild shampoo. Make use of proper use of 6 hours sleep.

My first questions would be about a marked change in diet.
Can you tell us what you used to eat in Nepal, and what you eat now?
Hair loss is often associated with a lack of the full range of B vitamins. Also too much sugar.

First of all, ask question yourself. What you used to eat so the problem happening with you? Secondly, try to eat food such as fruits and vegetables thereby you will get vitamins and proteins also. Third step is that talk to doctor about this issue.