Hello!~ 

Yeah~ walking is actually a best form of exercise. Not only that, according to most doctors, when you take a walk, happy hormones will also come out of your body, that's why you will feel happier after taking a walk. Isn't it fun?~ ^^ 

*Correction: 

Since one year ago, I have been hurting my back.

--> A year ago, my back has been hurting. 

*It's too hard exercise after work.

--> It's too hard to exercise after work.

*The gym is not opened on Sunday, so I take a walk to outside.

--> The gym is closed on Sunday, so I take a walk outside instead. 

*It was pretty boring for me at first, but now I came to like taking a walk to outdoor.

--> It was pretty boring at first, but now, I seemed to enjoy walking outdoor. 

 *I realized recently that I'm influenced from weather a lot. The day with cloud I feel a bit dipressing, but the day with sunshine my mood is higher. 

--> I recently learned that I am heavily influenced by the weather. I feel a little depressed on cloudy days, but on sunny days, my attitude improves.