i pulled a muscle?

This happen yesterday idk if i sleep on my arm but it really hurts alot i try to streatch my arms it kinda feels alittle better because im resting my arm how can u make ur arm feel better again the pain still their my self always pulling a muscle aall the time i hate doing that that hurt like if someone killing u like putting a knife in ur arm or sometime i pull a muscle in my leg .... like wat to do can u help me out wats a better way to get the pain not their any morre....