Can't be good for the twins

I have this unbearable pain for 2 days in my back my back always hurts but this is just to much!!!! I don't wanna bug my doc if I don't need to being in not a fan of him!! I'm 31+5 days with twins! I'm seriously losing my mind, I'm at my wits end!!! Plzzzz what can I do, I have tried everything!!!