So I sleep on my stomach with my hands on my pillow, under my face.

I've been sleeping this way for as long as I can remember. I can't fall asleep on my back or my side. Its never caused any problems until about two weeks ago.

I started waking up at night from intense pain in my right hand and arm. Just my right one. I'm pretty sure its caused my sleeping the way I do because I wake up in so much pain but then I roll onto my side and straighten my arm out and it goes away after a few minutes.. then I roll back over and go to sleep and wake up a few hours later with the same pain. I've been trying to sleep on my side and back but I can't fall asleep unless I'm on my stomach.

I still don't know why it only started two weeks ago even though I've been sleeping this way for most of my life. So my questions are 1) why did it only start recently 2) should i see a doctor? and 3) how can I learn to fall asleep on my back/side?