What Causes Lightheadedness,tingling And Numbness In Lip And Leg?

hi. im 16 years old, and im just worried because my arms go tingling and numb, the sides of my lip burn or go numb, and my left leg sometimes goes numb. My pulse always feels fine, and i think it may be my nerves. Im always lightheaded too, but tht may be from being tired. I just want an explanation and know im not dying or about to lose the ability to move.