So Lately, For The Past 3 Weeks Or So, I've

So lately, for the past 3 weeks or so, I've been having restless sleeps. I go to sleep and wake up every couple hours. I'm super tired all the time. My body is sore and achy. My back hurts. When I wake up I can barely breathe and I have heart burn every morning when I wake up. My eyes have started twitching...A LOT. Ive been falling asleep in class and waking up with heart burn then too. I'm 16. Why is this happening?