Why Do I Always Stress Out?

To me stress comes from lack of control. When we don't have control we tend to become stressed and when we are finally able to regain that control we tend to become less stressed. This answer isn't proven, its just how i tend to look at life. Hope it helps

I think whiteboys is correct.  Often, it is from lack of control.  It is important to try to come up with a plan to tackle certain obstacles or problems.  This can help lessen stress and when it is something absolutely out of your control, which many problems are out of your control.  Try to find activities to lessen stress and relax like reading, exercising, etc.  Accept the things you cannot change, but easier said than done.

The main reason why people stress out is because you have little to no acceptance in your world. Not accepting the fact that you can not control anybody but your self; your thoughts, actions, moods, and behaviors. You can not change people to who, what, when , where, and how you want them to be.
Reciting the sincerity pray often helps relieve stress and helps remind your self that you can only do what is in your power to do. And it goes like this,  "God grant me the sincerity to accept the things that I can not change, the courage to change the things that I can, and the wise to know the difference."

You probably do what I do and worry about everything going on in your life without really realizing it. Be careful you don't fall into depression. Then everything will turn upside down.

Because you are probably made or frustrated by something or at something

You might want to be checked for ADD.  It can cause stress on almost every level of your life.

Pubity. Growing up. Probably mood swings.

Maybe you need some me time...... Time were you get away from the world, and relax, go some where you can clear your head. Wen you can control your own life maybe you want need to control others

Negative thoughts and closed-in places being lonely

You may not get enough sleep or get nervous